Chocolate Lava Cakes

These are rich tasting and fun to make.  From Readers Digest February 2012.

Centres
2 oz (60g) Bittersweet chocolate, chopped
1/4 cup whipping cream

Cakes
1/2 cup unsalted butter, cut into pieces
4 oz (125 ml) bittersweet chocolate, chopped
2 whole eggs
2 egg yolks
1/3 cup granulated sugar
1/2 tsp pure vanilla extract
1/4 cup cake and pastry flour

1. To make centres:  In double boiler or heatproof bowl set over pot of barely simmering water, melt 2 oz chocolate with the cream, stirring occasionally, until smooth.  Refrigerate until firm, about 1 hour.  Form into six balls; refrigerate until needed.
2. To make cakes:  Preheat oven to 350F.   Grease six 6 oz ramekins or custard cups; place on baking sheet.
3. In double boiler or heatproof bowl set over pot of barely simmering water, melt butter and 4 oz chocolate, stirring occasionally until smooth.
4. With stand mixer or in large bowl with electric beaters, beat the whole eggs, egg yolks, sugar and vanilla on high speed for about 5 minutes, or until thick and light.  Fold melted chocolate mixture and flour into egg mixture until just combined.  Spoon cake batter into ramekins.  Place a chocolate ball in the middle of each ramekin, making sure each is completely covered by batter.
5. Bake for about 15 minutes or until cakes are firm to the touch.  Remove from oven and let sit for about 5 minutes before serving.