- ½ cup unsalted butter, plus more for buttering the molds
- 4 ounces bittersweet or semisweet chocolate, chopped into small pieces
- 4 large eggs
- ¼ cup sugar
- 2 teaspoons flour, plus more for dusting the molds
- Put the butter in a medium bowl and melt it in the microwave. Add the chocolate to the hot butter and stir until melted.
- Crack 2 eggs into a bowl, and add 2 more yolks (discard the extra whites). Add the sugar, and beat or whisk until light and thick, about 1 minute. Add egg mixture and 2 teaspoons flour to the melted chocolate; beat until combined.
- Butter and lightly flour four 4-ounce molds or ramekins (make sure not to miss any spots, or the cakes will stick). Tap out the excess flour. Divide the batter among the molds. (At this point you can refrigerate them for up to 3 hours; just bring them back to room temperature before baking.)
- When you’re ready to bake, heat the oven to 450. Put the molds on a rimmed baking sheet and bake until the cakes have puffed up a bit, the tops are barely set and the cakes still jiggle slightly when shaken, 7 to 9 minutes (better underbaked than overbaked). Let sit for 1 minute.
- Put a plate on top of the ramekin and (with a potholder to protect your hand) carefully invert the cake onto the plate. Let it sit for 10 seconds, then lift up the ramekin. Serve immediately, with ice cream, sorbet or whipped cream.