Preheat the oven to 375°F (190°C). Butter the ramekins thoroughly. Coat the inside with a small amount of sugar, then shake out any excess.

Melt the chocolate and butter together using a double boiler or by microwaving in 15-second intervals, stirring until smooth. Allow to cool slightly.

Add the egg yolks, vanilla extract, and salt to the melted chocolate. Whisk until smooth and fully combined.

Beat the egg whites in a clean bowl until soft peaks form. Gradually add 2 tablespoons of sugar, one spoonful at a time, and continue beating until stiff, glossy peaks develop.

Fold one-third of the whipped egg whites into the chocolate mixture to lighten it. Gently fold in the remaining egg whites in two batches until just combined, being careful not to deflate the mixture.

Divide the batter evenly between the prepared ramekins, filling each about three-quarters full. Smooth the tops gently if needed.

Place ramekins on a baking sheet and bake for 14-16 minutes, or until the soufflés have risen and the tops look set. The centers should remain slightly soft.

Dust with powdered sugar, serve immediately and enjoy!