Brown Sugar Fudge Cake
Maple syrup and brown sugar unite in this unbelievably good cake.
Serves16 to 20
Prep30 minutes
Cook1 hour
Maple brown sugar has been the flavor combination of my dreams for as long as I can remember. (Granted, my Canadian birthright ensures my blood runs maple, so I feel bonded to the amber nectar — especially when I get my hands on the best maple syrup.) When these two team up, it creates an earthy, caramel-y, and bright flavor profile that’s anything but one-dimensional, and that’s what this brown sugar fudge cake is all about.
This cake relies on all brown sugar for flavor and sweetness, whips up quickly, and bakes in a rectangular pan (a metal pan is best) for a single-layer, tall sheet cake that you can serve straight from the pan. But the frosting is what sets this cake apart. Inspired by sucre à la crème (maple fudge), maple cream, chocolate fudge, and penuche (a boiled brown sugar frosting), the topping borrows something from each dessert to create a unique frosting that’s creamy and smooth, lighter than fudge, but firmer than a glaze. It does take extra time and attention between boiling sugar and beating it until thick, but the final result is well worth the effort.
This cake tastes just as good the next day, if not better. And once it was refrigerated, I snacked on slivers for over a week and the cake stayed tender while the frosting did not lose its height or velvety texture. I highly recommend stashing a piece in the freezer for a future cake emergency.
Why You’ll Love It
- It’s sweet, but not too sweet. Although there is a hefty amount of brown sugar and maple syrup in the recipe, the tall, buttery cake and moderate amount of frosting keeps the dessert from becoming a sugar bomb.
- The frosting doesn’t rely on powdered sugar or butter. The unique, thicker-than-a-glaze, fudge-like frosting isn’t as heavy as buttercream and does not have the signature sweetness of a powdered sugar-based frosting.
Key Ingredients in Brown Sugar Fudge Cake
- Light brown sugar: Soft brown sugar is essential for baking up a soft cake and evenly cooking the frosting. If your sugar is hard, there are some quick ways to soften brown sugar before baking.
- Maple syrup: This recipe is not a place for pancake syrup or sugar-free syrup, as neither will boil correctly. Grade A amber pure maple syrup is ideal because it has a well-balanced flavor, is versatile, and easy to find. Robust maple syrup has a stronger taste and darker appearance, but a similar boiling point, so it could also be used.
- Sour cream: Sour cream doesn’t make the cake tangy, but it adds density to match the hefty frosting and works with the baking powder and soda to tenderize and lift the cake.
- Heavy cream: The richness of heavy cream prohibits curdling when boiled. Heavy cream and whipping cream are not exactly the same, but are interchangeable in this recipe.
- Maple extract: If you never noticed maple extract at the store, use this recipe as a nudge to pick up a bottle. A little goes a long way, and it boosts the maple flavor without tasting harsh or artificial.
How to Make Brown Sugar Fudge Cake
- Make the cake. The method uses standard technique of beating the butter and sugar together until light, then working in the eggs, and finishing by alternately adding the dry ingredients with the liquid ingredients until the batter is smooth, thick, and fluffy.
- Boil the sugar for the frosting. You can start making the frosting when the cake comes out of the oven or later. The cake can be slightly warm or totally cooled, as long as it’s not piping hot, which would cause the frosting to melt.
- Beat and spread the frosting. As you beat the cooled sugar mixture, the color and texture will change and become thicker than a glaze but still pourable. Be patient when whipping the cooked sugar mixture. It will seem like not much is happening for several minutes, but just stick with it and it will start to lighten and thicken. You can stop occasionally and stir a few times with a spatula to check the consistency and beat out some of the air bubbles. Once spread on the cake, the surface will quickly set, so let it be, or the texture will look messy and grainy.
Helpful Swaps
- If you choose to swap in salted butter, just cut the amount of salt in half to keep the cake balanced.
- Vanilla paste can stand in for extract. It will have a stronger taste and add some pretty flecks of brown to the batter.
Brown Sugar Fudge Cake
Maple syrup and brown sugar unite in this unbelievably good cake.
Prep time 30 minutes
Cook time 1 hour
Serves 16 to 20
Nutritional Info
Ingredients
For the cake:
- 2
sticks (8 ounces) unsalted butter, plus more for the pan, at room temperature
- 1 cup
whole milk, at room temperature
- 1/2 cup
sour cream, at room temperature
- 3
large eggs, at room temperature
- 3 cups
all-purpose flour
- 2 teaspoons
baking powder
- 1/2 teaspoon
baking soda
- 1 3/4 cups
packed light brown sugar
- 1/2 teaspoon
kosher salt
- 1 tablespoon
vanilla extract
- 1/2 teaspoon
maple extract (optional)
For the frosting:
- 2 cups
packed light brown sugar
- 1 1/4 cups
heavy cream
- 3/4 cup
maple syrup (not pancake syrup)
- 1/4 teaspoon
kosher salt
- 1/2 teaspoon
vanilla extract
- 3 tablespoons
unsalted butter, cut into 6 pieces
- 1/3 cup
chopped, toasted pecans or walnuts
Instructions
Make the cake:
Heat the oven to 350°F. Lightly brush the bottom of a 13x9-inch baking pan with room-temperature butter. Line the bottom and 2 long sides of the pan with a sheet of parchment paper, making sure the paper extends over the sides by a few inches to form a sling. Lightly brush the bottom and sides of the parchment with more butter. (If you want to serve the cake directly from the pan, skip the parchment and just lightly butter the pan.)
Whisk 3 cups all-purpose flour, 2 teaspoons baking powder, and 1/2 teaspoon baking soda together in a medium bowl. Whisk 1 cup room-temperature whole milk and 1/2 cup room-temperature sour cream together in a bowl or liquid measuring cup.
Beat 2 sticks room-temperature butter, 1 3/4 cups packed light brown sugar, and 1/2 teaspoon kosher salt with the paddle attachment in a stand mixer on medium-high speed, scraping down the sides of the bowl a few times, until lightened and creamy, 2 to 3 minutes total. Beat in 3 room-temperature large eggs one at a time, beating until each one is fully incorporated before adding the next. Beat in 1 tablespoon vanilla extract and 1/2 teaspoon maple extract if desired.
Reduce the speed to low. Beat in about one-third of the flour mixture until just combined. Add half the milk mixture and beat until combined (it’s OK if it looks slightly curdled). Repeat beating in the flour in two more increments, alternating with the remaining milk, scraping down the sides of the bowl as needed. Use a flexible spatula to finish mixing, making sure to scrape any dry flour bits from the bottom and sides of the bowl.
Scrape into the baking pan and spread into an even layer. Smooth out the top.
Bake until the cake is lightly browned on top and the center springs back to a gentle touch, 35 to 50 minutes. Let cool in the pan while you make the frosting.
Make the frosting:
Place 2 cups packed light brown sugar, 1 1/4 cups heavy cream, 3/4 cup maple syrup, and 1/4 teaspoon kosher salt in a large, high-sided saucepan (at least 3 quarts). Cook over medium-low heat, stirring frequently, until the sugar is dissolved and the edges begin to bubble, 4 to 5 minutes.
Attach a candy or deep-fry thermometer to the side of the pan and increase the heat to medium. Bring to a boil without stirring. Continue to boil until the mixture registers between 234°F and 238°F, 10 to 15 minutes. The sugar will bubble up vigorously. If it gets too close to the top of the pot, reduce the heat a bit but make sure it’s still boiling.
Remove the pot from the heat. Add 1/2 teaspoon vanilla extract, then add 3 tablespoons cut-up unsalted butter. Do not stir or disturb the pot. Let cool until warm but not hot (120°F to 130°F), 45 to 55 minutes.
Remove the thermometer. Stir with a stiff spatula or wooden spoon until fully blended and shiny. Transfer to a stand mixer and beat with the paddle attachment on medium speed until the color lightens to a light beige (like milky tea) and thickens enough that it can still be poured but a ribbon of the frosting will sit on top of the mixture without melting back into the pot and losing its shape, 30 to 35 minutes. (Alternatively, beat directly in the saucepan with an electric hand mixer, which will take 10 to 15 minutes.)
Transfer onto the middle of the cake. Gently spread with a small offset spatula, stopping just before the edges as the frosting will spread just a little on its own. Sprinkle with 1/3 cup chopped, toasted pecans. Let sit until the frosting sets and is firm, 1 to 2 hours. Grasping the excess parchment, lift the cake slab out of the pan onto a cutting board before cutting.
Recipe Notes
Substitutions: The toasty crunch of pecans or walnuts is delicious against the dense fudgy frosting, but for a nut-free cake you could use salted pumpkin seeds or sprinkles instead. If using sprinkles, opt for ones that are slightly larger than the tiny hard nonpareils so that they adhere to the top of the frosting and don’t just roll off.
Make ahead: The cake can be baked up to 1 day ahead, cooled, wrapped well, and stored at room temperature.
Storage: Leftover cake can be wrapped well or transferred to an airtight container and stored at room temperature for up to 1 week. After 1 day, the frosting where it meets the top of the cake will start to soften and soak into the cake, but the rest of the frosting will remain firm enough to slice and eat.
The frosted cake can also be frozen for up to 2 months. Thaw at room temperature (if only serving a smaller piece of frozen cake, cut before thawing).