- In a saucepan over low heat, melt the butter and chocolate together. Set aside.
- In a mixing bowl, combine the sugar and cornstarch. In a separate bowl, whisk the eggs and yolks together. Add the melted butter-chocolate mixture to the sugar mixture and combine thoroughly with a wire whisk. Stir in the eggs and whisk just until smooth. Place in the refrigerator 2-24 hrs- until firm.
- Preheat the oven to 400 degrees. Line 4 metal rings (about 2 I inches across and 2 inches high) with greased parchment paper. (Alternative, use 6 smaller molds or ramekins.) Line a baking sheet with parchment paper and set the molds on the sheet. Scoop the mixture into the molds so they are two-thirds full, and make sure the molds are not leaking.
- Bake on the top oven rack for 20 minutes. Remove the baking sheet from the oven, and while holding each mold with tongs, slide a metal spatula underneath, carefully lift, and transfer to a serving plate. Gently lift off the mold and remove the parchment paper. Serve immediately.