Best-Ever Chocoflan

Place 12 tablespoons of the unsalted butter in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Place the remaining 2 tablespoons unsalted butter in a 10-cup bundt pan. Place 3 large eggs and 1/2 cup whole or 2% milk on the counter. Let everything sit until room temperature.

Arrange a rack in the middle of the oven and heat the oven to 350°F. Generously grease the bundt pan with the butter, making sure to get into all the nooks and crannies of the pan. Measure out 1 cup granulated sugar. Sprinkle 1 tablespoon of the sugar into the bundt pan and shake and tap to evenly coat; add the remaining sugar to the bowl of butter.

Place 1 1/2 cups all-purpose flour, 1/2 cup Dutch processed unsweetened cocoa powder, and 2 teaspoons baking powder in a medium bowl and whisk to combine.

Bring about 10 cups water to a boil in a tea kettle or small pot, then turn off the heat (keep the water covered). Meanwhile, make the caramel, finish the cake batter, and make the flan layer.

Place 1 cup granulated sugar and 1/2 cup water in a small heavy-bottomed saucepan. Bring to a boil over medium heat, stirring with a fork, until the sugar dissolves. Continue to boil, swirling the pan occasionally but not stirring, until a light amber brown caramel forms (the mixture should be about 360ºF), 8 to 16 minutes. Carefully pour the caramel into the bundt pan.

Beat the butter and sugar with the paddle attachment on medium speed until very light and fluffy, about 5 minutes. Beat in the room temperature eggs one at a time, beating thoroughly after each addition. Add 2 teaspoons vanilla extract and 1/2 teaspoon kosher salt and beat until combined. Scrape down the sides of the bowl.

Add 1/3 of the flour mixture and beat on the lowest speed until just combined. Add 1/2 of the milk and beat on the lowest speed until just combined. Repeat beating in half of the remaining flour, then the remaining milk. Finish beating in the remaining flour.

Remove the bowl from the stand mixer and stir with a flexible spatula to make sure all the flour is incorporated. Dollop the cake batter over the caramel in the bundt pan and spread into an even layer.

Place 4 cold large eggs in a blender and blend on low speed until broken up, about 10 seconds. Add 1 (14-ounce) can condensed milk, 1/2 cup heavy cream, 2 teaspoons vanilla extract, 1 1/2 teaspoons all-purpose flour, and 1/2 teaspoon ground cinnamon. Blend on high speed until smooth, about 1 minute.

Hold a large spoon over the cake pan and slowly pour the flan mixture onto the spoon over the cake batter (this will help keep the batters separate).

Coat a sheet of aluminum foil with cooking spray. Place spray-side down over the bundt pan and tightly cover. Place the bundt pan into a 9x13-inch baking dish. Place the baking dish on the oven rack. Pour enough hot water into the baking dish to go about halfway up the sides to create a water bath.

Bake until a tester inserted into the cake layer (which will have switched places with the flan during baking) comes out mostly free of crumbs, 1 to 1 1/2 hours.

Remove the bundt pan from the baking dish and place on a wire rack. Uncover and let cool for 1 hour.

Run a thin knife around the chocoflan and around the center column. Invert a serving platter or large dinner plate over the bundt pan. Carefully but confidently invert the dinner plate and bundt pan in one motion; remove the bundt pan. Refrigerate until chilled through, at least 4 hours or up to overnight. Cut into slices and serve.