Topping
Into a saucepan, add the sugar, the eggs, the wheat flour, mix it all together very well until combined, add the yogurt, mix again until combined.
Bring to a boil over medium to low heat and mix well until slightly thickened. As soon as you turn on the heat, add the vanilla essence and continue to mix until it thickens.
Turn off the heat and add the butter, stir well until fully combined.
Transfer the cream to a bowl, cover it with plastic wrap making sure it touches the surface of the cream, and set aside.
Get an 18cmx18cm square cake mold and place a sheet of acetate cake collar inside the mold (if you don't have a mold, use a regular baking dish). Make a layer with the chocolate biscuits, cover them with a layer of cream. You'll be making 3 layers of cream and 4 layers of biscuits, the final one being a biscuit layer. Set aside.
Into another saucepan, add the sugar, the table cream and the cocoa powder. Mix well until it slightly thickens, turn off the heat and add the butter, stir until well combined.
Pour this mixture into the mold, covering the last layer of biscuits. Spread well.
Place in the fridge and leave for at least 6 hours, or overnight.
Unmold and serve.