Cookie Dough

1. Take the butter out of the fridge at least 30 minutes before starting the recipe so it has the time to soften.
2. Whisk together the softened butter, cane sugar, and white sugar.
3. Add the whole egg and the egg yolk.
4. Lastly, gradually add the flour, cornstarch, salt, and baking soda.
5. Using a knife, cut both of the chocolates into chunks and add to the dough.
6. Roll into a log about 10 cm in diameter, wrap in plastic wrap and refrigerate for 2 hours to make cutting the dough easier.
7. Preheat the oven to 160°C (320°F).

Brownie Batter

1. Preheat the oven to 170°C (340°F).
2. Melt the chocolate in a double boiler, then add the butter.
3. Combine until smooth and warm.
4. Stir in the brown sugar, superfine sugar, and egg yolks. Stir again.
5. Sift in the flour and cocoa powder, add the walnuts, then fold in the egg whites. Stir gently.
6. Pour the batter into the 12 muffin mold, on top of the cookie dough, and bake for 18-20 minutes at 160°C (320°F).
7. Unmold and add the toppings of your choosing.