impossible caramel cake

Ingredients
For the dough:
85 g powdered sugar
110 g butter
125 g flour
20 g unsweetened cocoa powder
3 g baking soda
3 g baking powder
1egg
160 ml of coffee
For the layer of Flan
400 ml unsweetened condensed milk
350 ml sweetened condensed milk
3 whole eggs + 2 yolks
2 tsp vanilla extract
For the caramel
180 g sugar
3 tablespoons of water

Preparation
Preheat the oven to 180°C.
Place a typical frying pan and fill with water halfway up
Grease and flour a standard chimney pan and tap to remove excess.
Prepare the caramel: Put the water and sugar in a saucepan and cook over medium-high heat to obtain a beautiful golden caramelization color.
Pour it immediately on the bottom of the buttered mould as well as the edges.

Preparation of the dough:
Sift together the flour, cocoa powder, baking powder/baking soda and salt. Set aside.
In a bowl with an electric mixer, cream the butter and add the sugar until the mixture takes on a smooth and light texture.
Complete with the egg and whisk well before adding the sifted mixture of the dry ingredients alternately with the coffee until the mixture is smooth.
Pour the batter into the pan over the caramel. Smooth the surface with a spatula.

Blank preparation
In a blender pour the ingredients of the flan
Mix until you get a homogeneous texture.
Slowly pour the liquid mixture of the flan through a fine sieve.
Cover with aluminum foil and place the pan in the one containing the water.
Lower the oven temperature to 160°C and cook in a double boiler for about 1h15 min, until the tip of a pressed wooden skewer comes out dry.
Remove the cake from the oven and let cool completely to room temperature
Pass the knife blade all around the mould and unmould neatly on a serving platter.
Cover with caramel before serving.