For the caramel sauce you will need to start early...the night before. Place 1 can of sweetened Condensed milk in a large soup pot (remove label before you put the can in the water) Cover the can with hot water -make sure you have the can covered with at least 2 inches over the top. Bring to a boil reduce heat to med-high. Do not boil at a rapid boil. Doing so can cause the can to explode. Boil for at least 2 hours. if you prefer a darker caramel boil for 3 hours. Remove pot from heat and cool completely leaving the can in the water.( I let mine sit overnight ) Once you are ready to use (or transfer to another container) put the can in hot not boiling water for a few minutes to smooth the caramel. Open the can an use immediately or pour in a mason jar and save for later. This recipe will only use half of the sauce.
If all of this is too much trouble or too time consuming a jar of store bought works too.
Preheat oven to 350°
For the cake- you can prepare a store bought boxed mix per the box directions or, Sift together the dry ingredients(flour,salt, baking powder, baking soda, cocoa and sugar) Add oil,coffee and milk. Mix at medium speed for 2 minutes. Add eggs and vanilla and beat for 2 more minutes. The batter is thin-skinned don't panic.
Spray or oil a large Bundt Pan Pour 1/2 cup of caramel into pan and spread it out evenly. Set aside
For the Flan In a blender combine cream cheese (softened), 4 eggs, 1 can of sweetened Condensed milk , 1 can evaporated milk and 1 tsp vanilla. Blend until combined and smooth. Pour flan through a sieve into a measuring cup (just to make it easier to pour ). Pouring through a sieve will ensure that you don't have unicorperated cream cheese in the Flan it will also remove the tiny air bubbles that blending caused. If you like a lumpy Flan feel free to skip the sieve. Set aside.
Pour the cake batter into the Bundt Pan over the Caramel. Pour the Flan over the cake. the Flan will sink through the cake as it bakes.
You will need a roasting pan or other large pan with 1 inch of hot water in the bottom. Place the Bundt Pan in the roasting pan and cover Bundt Pan with foil. Bake for 1 hour Remove foil baked for an additional 30-40 minutes until a knife inserted into center comes out clean.
Remove from water and allow to cool for a minimum of 1 hour. Place cake plate over Bundt Pan and invert. Cover and refrigerate. serve chilled .