• Preheat the oven to 350°. Grease a 12-cup capacity Bundt pan (preferably nonstick) with 2 tablespoons of butter. Be sure grease it well, getting into all the nooks and crannies.
• Drizzle the caramel sauce across the bottom of the pan and set aside until ready to use.

Make the Cake Batter

• In a medium-sized mixing bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt. Set aside.
• Add the room temperature butter and the granulated sugar to a large mixing bowl and beat on medium-high speed for until light and fluffy, 3-4 minutes. You could also use a stand mixer fitted with a paddle attachment.
• Add the egg and the egg yolk and mix well to combine. Scrape the sides and the bottom of the bowl and mix once more.
• Add a third of the flour mixture and mix on low, followed by half of the buttermilk, again, mixing on low. Repeat this process until all of the flour has been mixed in. Add the batter to the pan and smooth across the top.

Make the Flan

• In a blender combine the evaporated milk, sweetened condensed milk, cream cheese, eggs, the egg white, vanilla extract, and salt. Blend on high for 30 seconds.
• Pour the flan over the chocolate cake layer. It is ok if the two seem to mix, they will separate while baking.

Bake the Cake

• Seal the cake tightly with a layer of nonstick aluminum foil and transfer to a large roasting pan. Add hot water to fill by 1".
• Bake on the center rack for 1 hour and 20 minutes. Remove from the water bath and allow the cake to cool completely for 3 hours.
• Delicately, run a sharp knife along the edges of the Bundt pan. Invert a large, rimmed serving platter or cake stand over the Bundt pan, hold tightly together, jiggle a little bit, and then carefully flip over. Garnish with extra caramel sauce, chocolate sauce, or pecans, desired. Keep refrigerated until ready to serve.