Preheat the oven to 400 F (200 C).
Butter and sugar 6 cups (with a capacity of 250 ml), oven-proof, and reserve them in the refrigerator while preparing the soufflés.
Place the chocolate and 1/2 cup of sugar in a double boiler. Mix until the chocolate is melted.
Off the heat, add the egg yolks and mix well.
Add the milk and mix.

Beat the egg whites until soft peaks form, then add the 2 tablespoons of sugar to stiffen them. Beat until stiff peaks form.

Add the egg whites to the chocolate mixture, gently folding with a spatula.

Divide the mixture among the prepared molds, and place them on a baking sheet.
Bake for 25 minutes.

Remove from the oven, dust with powdered sugar, and serve immediately.