Brush the insides generously with softened butter.
Use upward brush strokes along the sides of each ramekin.
Add the extra tablespoon of granulated sugar.
Turn the ramekins until their interiors are evenly coated.
Tip out any excess sugar.
Melt the dark chocolate in a double boiler or microwave-safe bowl.
Stir until completely smooth.
Allow the melted chocolate to cool for 3 to 5 minutes.
Place the egg yolks and 50 g sugar in a mixing bowl.
Whisk until pale, thick, and creamy.
Gradually whisk the melted chocolate into the yolk mixture.
Place the egg whites in a clean, grease-free mixing bowl.
Beat until they form soft peaks.
Gradually add the remaining 50 g sugar.
Continue beating until the whites form glossy medium-stiff peaks.
Fold one-third of the whipped egg whites into the chocolate mixture.
Gently fold in the remaining egg whites in two additions.
Stop folding as soon as no white streaks remain.
Divide half the batter among the prepared ramekins.
Place one piece of white chocolate in the center of each portion.
Cover the white chocolate with the remaining batter.
Fill each ramekin no more than three-quarters full.
Run a clean fingertip around the inside rim of each ramekin.
Bake for 12 to 15 minutes.
Remove the soufflés when they have risen and the edges look set.
Dust lightly with powdered sugar.
Serve immediately while the centers remain warm.
Notes & Wine Advice
Serving Suggestions
Serve each soufflé immediately with fresh raspberries, strawberries, lightly whipped cream, or a small scoop of vanilla ice cream. Have every garnish ready before the soufflés enter the oven because they begin settling soon after baking.
Recipe Notes
Use clean, grease-free equipment when whipping the egg whites. Even a small amount of fat can prevent them from reaching the required volume. Fold gently and stop as soon as the mixture looks even. Overmixing removes the air needed for a good rise.
Dietary Information
This recipe contains eggs and milk. Pure chocolate can contain soy lecithin and may share equipment with nuts, gluten, or wheat. Use chocolate and powdered sugar carrying suitable allergen information before classifying the finished dessert as gluten-free, wheat-free, or nut-free.
Nutrition Information
The values apply to one complete soufflé and include the butter, sugar coating, white chocolate center, and powdered-sugar garnish. The original estimate of 290 calories was too low for the stated quantities of dark chocolate, white chocolate, sugar, and eggs.
Variations
Replace the white chocolate center with milk chocolate, salted caramel chocolate, or a chocolate truffle. Add finely grated orange zest to the dark chocolate mixture for a citrus variation. A pinch of espresso powder can deepen the chocolate flavor.
Storage
Soufflés taste best directly from the oven and do not store well after baking. The filled ramekins can be covered and refrigerated for up to four hours before baking. Add 1 to 2 minutes to the baking time when cooking them directly from the refrigerator.
Wine Advice
Pair the dark chocolate with a sweet fortified Banyuls. Its dark fruit character complements the cocoa while balancing its slight bitterness. A sweet Riesling provides a fresher alternative that works particularly well with the molten white chocolate center.