FILLING: Melt 2 ounces of chocolate with heavy cream in a double boiler over simmering water. Whisk gently to blend. Refrigerate for about 2 hours, or until firm. With your hands, form into six balls, refrigerate until needed.
CAKE: Preheat the oven to 400 degrees. Spray six 4-ounce ramekins or custard cups with cooking spray. Melt 4 ounces of chocolate and butter in double boiler over simmering water, whisk gently to blend. In a large bowl, with an electric mixer, beat whole eggs, egg yolks, sugar, and vanilla on high speed for about 5 minutes, or until thick and light. Fold the melted chocolate mixture and flour into egg mixture just until combined. Spoon the cake batter into the ramekins. Place a chocolate ball in the middle of each ramekin. Bake for about 15 minutes, or until the cake is firm to the touch. Remove from the oven and let sit for about 5 minutes. Run a small, sharp knife around the inside of each ramekin, place a plate on top, invert and remove the ramekin.
Garnish with raspberries and a dollop of whipped cream.