For the Chocolate Mousse (do this first to let it chill):
1. Separate the egg whites from the yolks.
2. Melt the chocolate in a bain-marie.
3. Add the egg yolks to a food processor bowl and whisk. Then add the melted chocolate and continue whisking.
4. Whisk the egg whites until they form still peaks, then add a pinch of salt.
5. Gently fold the egg whites into the chocolate/egg yolk mixture in several batches.
6. Place the mousse in a large container and refrigerate for at least 4 hours, or overnight.
For the Cookie Cups:
1. Preheat the oven to 360°F.
2. Put the softened butter and sugar in a mixing bowl and mix with a hand mixer, standing mixer, or a whisk until combined. Add the egg and mix.
3. Add the dry ingredients and mix until it forms a ball.
4. Butter a muffin pan and press the dough into the moulds, shaping it into cups.
5. Place a large piece of parchment paper over the dough and pour dry beans or baking beads in each indentation so that they keep their shape.
6. Bake for 12 minutes, then remove the beads and the baking paper.
7. Continue cooking for 5 minutes until the cookie cups are golden brown. Remove from the oven and let them cool them on a rack.
8. Remove the cups from the muffin tin once they have cooled down. Add the mousse into the cooled cups using a fluted pastry bag, or a LE TUBE Pastry Press. Enjoy immediately.