For the caramel: In a nonstick skillet, add 1 cup sugar and a capful of vanilla extract. Cook over low heat until melted. Pour into a 12-inch (30 cm) cake pan and set aside.
For the flan: Blend 1 package cream cheese, 1 can sweetened condensed milk, 1 can evaporated milk, 6 eggs, and 2 capfuls of vanilla extract until smooth. Pour this mixture into the pan over the caramel.
For the cake: Prepare the chocolate cake mix according to the package instructions, using 3 eggs, 1 tablespoon (20 ml) neutral oil, and 1 cup milk (about 240 ml) until you get a thick batter.

Pour the chocolate cake batter over the flan mixture in the pan. The cake batter will sink below the flan layer. Cover tightly with aluminum foil to prevent water from getting in.
For baking: Light a wood fire. Place a large pot on the fire that fits your 12-inch (30 cm) cake pan. Add water to the pot until it reaches halfway up the side of the cake pan, making sure no water gets inside the pan.

Make sure the water stays boiling and doesn't run dry.
Cover the pot and cook for about 1 hour and 40 minutes to keep the heat in.
Check with a fork after this time; if it comes out clean, it's done. If not, cook for 20 minutes more.