1/4 cup heavy cream (sometimes I use milk)
4oz dark chocolate bar
1 stick unsalted butter
2 egg yolks
1/3 cup sugar
1/2 tsp vanilla
1/4 cup cup flour
To make the centers, melt chocolate chips and cream in a microwave. Whisk until well blended. Refrigerate for 2 hours or until firm. Form into 6 balls and refrigerate until needed.
To make the cake, melt chocolate ball and butter in the microwave. Whisk until well blended. With an electric mixer, whisk eggs, yolks, sugar and vanilla on high speed for about 5 minutes, or until thick and light. Fold melted chocolate mixture into egg mixture until just combined. Mix in flour. Spoon the cake mixture into 6 greased ramekins. Place a chocolate ball in the middle of each ramekin.
Bake at 400 for 15 minutes. The cake should be firm to the touch. Let stand for 5 minutes. Run a knife around the edge of the ramekin and place a plate on top, invert and remove ramekin. Serve with ice cream or powdered sugar or whipped cream and berries.