Melt the butter and cool it for approximately 5 minutes - you don't want the butter too runny and pooling in the bottom of the ramekin. Alternatively use super-soft butter that you can easily spread with a pastry brush.
Brush the butter all over the inside of the ramekins - bottoms and up the sides. Next place 2 teaspoons of granulated sugar in each ramekin and shake the sugar so it coats the bottom and sides of the dish. Shake out any excess sugar.
Soufflés
Separate the egg yolks and whites into two different bowls, ensuring no yolk mixes with the whites.
Place chocolate and butter in a heat-proof bowl. Melt in your microwave in 20 second increments at 50% power, stirring between each heating. Let cool slightly.
Add egg yolks and vanilla to the bowl. Whisk until well combined.
Add ½ teaspoon salt to bowl of egg whites. Using an electric mixer with the whip attachment, begin whisking until whites become foamy.
Begin adding the sugar slowly while continuing to mix. Keep whipping the whites until stiff, glossy peaks are formed.
Fold the egg whites into the chocolate mixture in two additions. Using a rubber spatula gently fold after each addition taking care not to deflate the whites, but you also don't want any white streaks.
Place the bowl in the refrigerator for 20 minutes. Cover the bowl with plastic wrap if the batter will be in the refrigerator for more than a few hours.
Baking & serving soufflés
Preheat oven to 375℉ / 190℃.
Divide soufflé batter between the 4 prepared ramekins.
Bake for 8 - 10 minutes. The center will still be jiggly but the top should look well risen and uniform.
Immediately move the soufflés to serving plates using caution as the ramekins are scorching hot.
Sprinkle with confectioners' sugar and place a few berries on the serving plate if desired.
Within a few minutes the soufflés will start to deflate but, don't worry, you have time to get them to the dinner table. Also, they do need to cool slightly before consuming.