Preheat to oven 350°F. Set a kettle of water to boil for a water bath. Grease a large 12-cup Bundt or tube pan and place inside a larger baking pan such as a roasting pan. Set aside.

In a small saucepan over medium-low heat, melt sugar until completely dissolved. Watch carefully so it does not burn. You may swirl the pan to stir. Remove from heat when it becomes amber or dark golden in color.

Immediately pour the melted sugar into the bottom of the cake pan, working quickly before it hardens. Set aside.

In a blender, combine cream cheese, sweetened condensed milk, evaporated milk, eggs and vanilla until smooth. Pour into pan over caramel sauce.

In a large bowl with a mixer, prepare cake mix according to the package instructions. Carefully pour over flan until pan is 3/4 full (extra batter can be used for cupcakes). DO NOT stir the flan and cake batter together.

Pour hot water into large baking dish so that water comes halfway up the sides of the Bundt pan. Bake for 60-75 minutes, checking for doneness after 1 hour. A toothpick inserted near center should come out clean.

Remove cake from water bath and cool on wire rack. For best results, refrigerate overnight before unmolding. Place a serving plate over cake and then flip plate and cake together, right side up. Remove cake pan and serve. Store leftovers in refrigerator.