Chocolate Pastry Cream for Filling

Preparation

1. Leave the necessary butter at room temperature for about 30 minutes until it is soft and easy to handle.
2. Separate the yolks from the whites, ensuring that no trace of yolk remains with the whites.
3. Beat the yolks with the sugar and cornstarch in a bowl until you obtain a homogeneous and light-colored mixture.
4. In a saucepan, bring the milk to a boil over medium heat, stirring occasionally to prevent it from sticking to the bottom.
5. Gradually incorporate the hot milk, in a fine stream, into the bowl with the yolks, stirring constantly to prevent them from curdling.
6. Return the mixture to the saucepan and heat it over medium heat, stirring constantly with a spatula, until it thickens and reaches the consistency of a cream, approximately for 5-7 minutes.
7. Once the cream has thickened, transfer it to a clean bowl and add the chopped chocolate. Stir continuously until the chocolate is completely melted and well incorporated.
8. Add the softened butter, cut into small cubes, stirring until it melts and mixes well with the cream.
9. Cover the cream with plastic wrap in direct contact with the surface to prevent a skin from forming.
10. Allow to cool at room temperature. Note: You can use it as is or chill it in the refrigerator. If chilled, slightly whip it with a hand whisk before serving to fluff it up a bit.