1. Preheat the oven to 350°F.
2. Melt the chocolate in a double boiler. Add the butter, stirring the mixture with a whisk.
3. In a bowl, whip the eggs and sugar. Add the flour mixed with pepper, then the melted chocolate, stirring without stopping.
4. Grease the individual molds and fill them halfway with dough.
5. Place a chocolate square in the center and distribute the remaining dough.
6. Bake for 10 minutes.
7. Remove from the oven and serve.