This recipe depends on well-beaten eggs for volume - room temperature works best. The cakes will puff nearly to the top of the dishes toward the end of bake time. Remove from oven at the first sign of cracks on the edges and when the center is still moist.
Directions
Preheat oven to 190°C. Generously coat 6 ramekins or custard cups with butter. Melt chocolate and 5 tablespoons butter in a medium-size microwave-safe bowl on medium (50 percent) power 2 minutes, stirring after 1 minute. Return to microwave if needed, stirring until completely melted. Do not overheat. Beat eggs, sugar and vanilla 3 to 5 minutes or until lemon colored and about tripled in volume, with an electric mixer. Stir cocoa powder and half egg mixture into melted chocolate. Gently fold chocolate-egg mixture into remaining eggs until thoroughly blended, but still fluffy. Pour half batter into prepared ramekins (about 3 tablespoons each). Place 3 to 4 raspberries or blackberries in centers. Top berries with remaining batter. (Can cover at this point and refrigerate up to 24 hours before baking.) Bake 13 to 15 minutes (16 to 18 minutes if refrigerated) until puffed and slightly cracked on edges and centers are still moist. Cool 2 minutes. Run a knife around edges. Using hotpads, invert cakes onto dessert plates. Surround with remaining berries.
Serve warm with ice cream.