Make the flan: In a blender, combine the dulce de leche, evaporated milk, cream cheese, vanilla extract, and salt and blend until smooth, 20 to 30 seconds. Pour in the eggs and blend for another 10 seconds until smooth.
Make the chocolate cake: Sift the flour, sugar, cocoa powder, baking soda, baking powder, salt, and cinnamon directly into the bowl of a stand mixer fitted with a paddle attachment, or a large bowl for use with an electric handmixer. Mix on the lowest setting until just combined, then add the softened butter and continue mixing on low speed until the mixture resembles wet sand. Stop the mixer and scrape down the sides of the bowl if needed.
In a liquid measuring cup, combine the coffee, buttermilk, egg, and vanilla extract, then slowly pour it into the flour-butter mixture with the mixer running on low. Scrape down the sides of the bowl and beat the mixture on high for a full minute.
Bake chocoflan: Liberally coat a 10-cup (2.5 liter) Bundt pan with cooking spray. [I’m using this one.] Add the cake batter, smoothing out the top with an offset spatula or spoon. Carefully ladle in the flan so you disturb the cake batter as little as possible. Transfer the Bundt pan to a roasting pan or baking dish large enough to fit the Bundt pan. Grease a piece of foil and place it greased side down onto the Bundt pan, folding it over the edges to loosely seal it. Transfer to the oven, then pour water (from the tap is fine) into the roasting pan or baking dish to come up 2 to 3 inches.
Bake for 2 hours to 2 hours 15 minutes, checking for doneness after 1 hour 45 minutes, using a skewer inserted into the cake to make sure it’s baked through, with little to no crumbs sticking to the skewer when you pull it out.
Carefully remove the Bundt pan from the roasting pan and let it cool to room temperature before placing it in the fridge to cool completely, at least a couple of hours.
To serve: Once you’re ready to serve, carefully run a knife around any edges that are still sticking, then invert onto a serving platter, gently shaking it up and down if it’s being difficult. If desired, serve with dulce de leche and a sprinkle of chopped nuts or with whipped cream and a sprinkle of cinnamon.
To make dulce de leche from sweetened condensed milk: I could not find a can of dulce at the grocery store so I needed to make my own for this recipe; give yourself time if you need to do this too. Even though you only need one can of dulce, and the volume will be the same as the volume of a can of sweetened condensed milk, you lose some volume when you make it, so I recommend making two cans worth. You’ll definitely have extra — it makes a little over 2 cups. You won’t regret it.
Pour the contents of 2 (14-ounce) cans sweetened condensed milk into a pie or medium casserole dish, and cover snugly with foil. Set plate in a large roasting pan and add enough hot water to pan to reach halfway up the smaller dish. Bake in a 425°F oven for 1 to 1 1/4 hours, or until it takes on a caramelized color. Set aside until cool, then whisk until smooth. For this recipe, you’ll need to measure 1 1/2 cups from the dulce de leche you’ve made. Save the rest for serving (a few flakes of salt will really liven it up). It will keep for weeks in the fridge, if not longer; rewarm in the microwave for 20 seconds, then stir, adding more time if needed.
To make dulce de leche fully from scratch (milk and sugar, no sweetened condensed milk): The Smitten Kitchen has you covered!