How To Make a Molten Chocolate Bundt Cake

updated Jan 21, 2020
How To Make a Molten Chocolate Bundt Cake

How to make a delicious, fudge-filled chocolate Bundt cake (a riff on Tunnel of Fudge cake) without a nut in sight.

Serves10 to 12

Makes1 bundt cake

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(Image credit: Maria Siriano)

When Ella Helfrich of Houston, Texas, won second prize in the Pillsbury Bake-Off® Contest in 1966 with her Tunnel of Fudge cake, she made more than just a winning cake — she created both a 1960s phenomenon and a memory that lingers so strongly for a generation of cake bakers and eaters that even though the ingredients she used are long off the market, many bakers to this day tackle her curious recipe. I recently joined those bakers. This is the story of how you can make a delicious, fudge-filled chocolate Bundt cake that’s all about the chocolate and fudge filling without a nut in sight, and that tastes like that memory.

(Image credit: Maria Siriano)

The Magic Behind the Original Cake

Pillsbury made a basic frosting mix for years, and the clever Mrs. Helfrich combined a packet with Pillsbury’s chocolate cake mix and baked it up in a newfangled, all-but-unknown decorative pan with a hole in the middle. The cake was dense with a variety of sugars, and a tunnel of fudgy gooey chocolatey goodness was the secret inside this innovative cake. Everyone wanted to make the cake. Bundt pan sales skyrocketed and the recipe itself was a national sensation.

No one could pinpoint how the magic tunnel o’ yum was created, but everyone reveled in the results.

The Tale of the Cake That Couldn’t Be Made

Then came a crushing blow to the tunnel o’ fudge bakers: Pillsbury dropped the more labor-intensive dry frosting packet and marketed the easier-to-use canned frosting. Home bakers suffered trying to recreate the cake, and they caused such an uproar that the company brought the frosting mix back for awhile and developed its own “from-scratch” version of the cake, which did not require their soon-to-be obsolete mix.

Not every baker was happy. There arose a zillion recipes for the cake, but most have glaring issues like gloppiness, soggy bottoms, runny middles, burnt outsides, or all of the above. Many use a variety of additive-laden packaged items and pudding, not fudge — none of which the original used — and they didn’t really create the same taste and texture. The biggest issue was that most offered inconsistent results. Then came a food scientist named Shirley O. Corriher.

In 2007 Corriher wrote Bakewise: The Hows and Whys of Successful Baking and offered up her brilliant and innovative version of the Tunnel of Fudge Cake. She upended the recipe by throwing all logic about cake baking ratios out the window, upping the sugar, enriching it with egg yolks, and baking it just so the fudgy center appeared like magic. It’s a great recipe, if quite sweet. A key to both her cake and the Pillsbury version is the use of nuts. Lots and lots of nuts. The nuts provide physical structure. My quest was different. This was to be a cake that didn’t need the architectural engineering of nuts.

(Image credit: Maria Midoes)

Many, Many Cakes Ensued

My recipe tester is a veteran baking chef-instructor. When I showed her my first three ideas for this cake, she checked the baking numbers and was aghast, but game. Not one fit any ratio of any cake she had ever made. We talked for hours and consulted textbook after textbook. There was no doubt that the cake would need odd ratios, but the issue was twofold: Could I come up with a hack to create a great cake and great filling, and could I make it all without the nut scaffolding? I revised and recalculated.

None worked as planned. My dense ganache filling was absorbed by the cake, my fudge candy dissolved, and the fudge-brownie based versions wouldn’t cook enough to invert and remove from the pan without oozing like mad. They were all delicious, mind you, but the texture was never right. That’s not good enough to make a memory live again.

Oh, Mrs. Helfrich, some 11 cakes later, I was checking numbers, and lo and behold I realized that I should probably try to use the best version I had come up with and see if it worked with nuts the classic way, and deal with one problem at a time. I added 2 1/2 cups of toasted chopped pecans and, darn, that recipe worked great, as if it was the original.

Note to baker: For a nut-filled version, go ahead and add that 2 1/2 cups of toasted chopped pecans.

I thought about what to do to make the darn thing without the nut scaffolding. I tried baking cakes with some logistical changes, like heating the pan, popover-style, before adding the batter, but the results were too inconsistent. I was many, many weeks in and now baking two cakes a day, and no one in my house or at my catering job wanted to eat it anymore. I woke up at 4 a.m. to bake two cakes before we attended an afternoon wedding. Obsessed? Just a wee bit.

Four more cakes with just a few tweaks and finally, finally, it worked. No nuts and it worked. The cake held up. I baked it twice again and had my sister, who does not bake, bake it. Sure, it sank a bit every time on the fudgy part, as does every Tunnel of Fudge cake I had ever seen. This cake had a distinct fudgy center, and a cake outside that was moist and cooked. It was easy to cut through and serve beautiful slices.

I must thank Ms. Corriher. Some technical advice is absolutely taken from her version, like baking the cake for a precise amount of time and not checking for doneness and also allowing it to cool completely in the pan, but mostly and yet again, what I learned was her scientific approach to baking. I hope you love it as much as we do in my kitchen.

Here’s what I added that helped make this recipe work.

  1. Scoop the batter in and smooth so the areas around the edges of the cake pan are less full.
  2. Bake the cake on the oven’s middle rack, and about halfway through the baking, slide a casserole dish filled about two-thirds of the way with warm water onto the rack below the cake. It will boil and add humidity to the oven and help the cake stay moist. Do not add it at the beginning. You have to let the sides, bottom, and top of the cake set well first, so adding the pan of water at the 25-minute mark works best.
  3. Poke holes in the finished cake around the edges of the entire pan. The ring of ooey-gooey chocolate in the middle of the cake sinks big time. While the cake is piping hot, poking some holes near the pan’s edges helps let that hot air out faster, so it catches up a bit with the center. The cake’s top will not be flat when it’s in the pan, but that’s just fine.
  4. If the cake has sunk more than you like, while it is still warm, if you have some pie weights or a pie weight chain, you can cut a parchment sheet to fit the tube pan (complete with a hole in the center), slide it on top of the cake, and place some pie weight around the inner and outer edges. Leave them there while the cake cools, 3 to 4 minutes.

This cake was delicious without the glaze, but the glaze does dress it up and adds a milkier chocolate layer of flavor. It’s really up to you if you want to gild this lily. Just make sure to have plenty of whipped cream or ice cream on hand and simply enjoy.

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Prepare a 12-cup bundt pan. Spray the inside and tube of a 12-cup nonstick bundt pan with cooking spray and set aside. Arrange a rack in the middle and a rack in the lower third of the oven. Heat to 350°F. (Image credit: Maria Midoes)

How To Make a Molten Chocolate Bundt Cake

How to make a delicious, fudge-filled chocolate Bundt cake (a riff on Tunnel of Fudge cake) without a nut in sight.

Makes 1 bundt cake

Serves 10 to 12

Nutritional Info


For the cake:

  • Cooking spray

  • 2 1/2 cups

    unbleached, all-purpose flour

  • 3/4 cup

    natural unsweetened cocoa powder

  • 2 teaspoons

    baking powder

  • 1/4 teaspoon

    baking soda

  • 1/2 teaspoon


  • 1/2 teaspoon

    espresso or instant coffee powder

  • 3 sticks

    (12 ounces) unsalted butter, at room temperature

  • 1 1/4 cups

    granulated sugar

  • 1 1/2 cups

    packed dark brown sugar

  • 2

    large eggs, at room temperature

  • 5

    large egg yolks, at room temperature

  • 3 1/2 ounces

    semisweet chocolate, coarsely chopped

  • 1/2 cup

    sour cream, at room temperature

  • 2 teaspoons

    vanilla extract or vanilla bean paste

For the glaze:

  • 4 1/4 ounces

    milk or white chocolate, finely chopped

  • 1/2 cup

    heavy cream, at room temperature, plus more as needed


  • Measuring cups and spoons

  • 12-cup nonstick Bundt pan

  • Mixing bowl or large sheet of parchment

  • Sifter

  • Stand mixer or handheld electric mixer

  • Rubber spatula

  • Microwave-safe bowl

  • Cooling rack

  • Serving platter or cake stand


  1. Prepare a 12-cup bundt pan. Spray the inside and tube of a 12-cup nonstick bundt pan with cooking spray and set aside. Arrange a rack in the middle and a rack in the lower third of the oven. Heat to 350°F.

  2. Sift the dry ingredients. In a large bowl or on a large sheet of parchment paper, sift together the flour, cocoa powder, baking powder, baking soda, salt, and espresso or coffee powder; set aside.

  3. Cream the butter and sugars. In the bowl of a stand mixer fitted with a paddle attachment, or in a large mixing bowl with a sturdy handheld electric mixer, combine the butter, brown sugar, and granulated sugar and mix at low speed until incorporated, about 2 minutes. Using a rubber spatula, scrape the sides and the bottom of the bowl well, making sure all of the mixture is in the middle of the bowl by the paddle or beaters. Increase the speed to high and mix until lighter in color and very fluffy in texture, 4 to 4 1/2 minutes. Don't worry if it still looks a bit grainy — the sugar will not and should not dissolve.

  4. Add the eggs and egg yolks. Add the eggs and egg yolks one at a time, beating after each addition just until mixed in, starting at low speed and increasing the speed to high until fully incorporated and fluffy again. Scrape down the sides and the bottom of the bowl between each addition.

  5. Melt the chocolate. Place the semisweet chocolate into a microwave-safe bowl and heat at medium power, in 20-second bursts and stirring between each burst, until the chocolate is just melted, 90 to 100 seconds total. Stir well and set aside to cool to room temperature while you start putting the cake together.

  6. Add the flour mixture to the egg mixture. Add the flour mixture to the egg mixture and mix on low to medium-low speed until combined. Scrape down the sides and the bottom of the bowl.

  7. Add the remaining wet ingredients. Add the sour cream, vanilla, and melted chocolate and mix at low to medium-low speed until combined.

  8. Fill the pan. Scoop the batter into the bundt pan. Using a spatula, smooth the surface around the outside perimeter of the pan and the inside tube so that it is 1/2 to 3/4-inch lower than the rest of the cake, to help keep the cake more even as it sinks while it cools after baking.

  9. Bake the cake. Bake on the middle rack for 25 minutes.

  10. Create some humidity. Place a 9- by 13-inch baking dish two-thirds filled with warm water on the lower rack and continue baking for 17 minutes longer. Remove from the oven and place the cake, in its pan, on a cooling rack. You will not be able to gauge doneness with a cake tester or toothpick. Don't fear the fudgy — that's how this cake works.

  11. Poke holes in the surface of the cake. Using a long, thin wooden or metal skewer, liberally poke holes in the top of the cake around the perimeter of the pan and around the inner tube part, about 24 pokes in total. The cake will sink in a ring shape as it cools, and poking holes will make that process more consistent and even. Allow to cool completely in the pan.

  12. Invert the cake. Place a serving platter or cake stand on top of the cake pan so that the bottom of the platter faces up. Holding the platter firmly with one hand, slide your other hand under the bundt pan and grip firmly. Flip the whole thing over gently but quickly, still holding firmly with both hands, so that the bottom of the pan faces up. Leave the pan over the cake while you make the glaze.

  13. Make the glaze. Place the milk or white chocolate and place in a heatproof bowl; set aside. Place the cream in a microwave-safe bowl and heat until it is very hot and almost boiling, in 20-second blasts, being careful not to let it spill or bubble over, about 1 minute total. Pour the hot cream over the chocolate and let stand until the chocolate is melted, about 2 to 3 minutes. Whisk until smooth and very thick yet pourable.

  14. Remove the cake pan and glaze the cake. Lift the pan from the cake. Gently pour the glaze over the top of the cake and allow it to drip down the sides liberally. Let the glaze dry and set for about 15 minutes before serving.

Recipe Notes

Storage: This cake will keep at room temperature, covered, for up to 2 days and the fudge part will firm up a bit over time.