1. Preheat the oven to 200°C (392°F).
2. Melt the butter and chocolate, cut into pieces, in a double boiler or in the microwave.
3. Add the sugar, whole eggs, praline, and sifted flour.
4. Mix vigorously until you obtain a homogeneous mixture.
5. Pour into a greased and floured cake pan.
6. Bake in the oven for 15 to 25 minutes, depending on the desired result (molten, fudgy, or more airy).
7. Unmold 20 minutes after removing from the oven.
Let cool on a wire rack, sprinkle with vanilla powdered sugar.