6tablespoons85 g; 3 oz unsalted butter, plus more for the molds
Flour of your choiceto dust the molds
4oz115 g dark chocolate (70% cocoa)
2large eggs plus 1 egg yolk
¼cup50 g; 1 ¾ oz blond cane sugar
½teaspoonfleur de sel
1teaspoonpure vanilla extract
3tablespoons22 ½ g; ¾ oz hazelnut or millet flour
1oz30 g hazelnut-flavored chocolate, cut into 4 pieces
Confectioners’ sugarto dust
Instructions
Preheat the oven to 450ºF (230ºC). Butter the ramekins, then coat them with flour and tap the excess out. Melt the dark chocolate and butter in a bain-marie.
In the bowl of a stand mixer, combine eggs, sugar, and fleur de sel and beat until the batter has tripled in volume and is light and pale in color (about 8 minutes). Add vanilla and fold in the flour, then the melted chocolate-butter mixture, making sure to keep the batter light each time.
Divide three-quarters of the batter among the ramekins and add one piece of hazelnut chocolate at the center of each mold. Cover with the rest of the batter. At this point, if you want, you can refrigerate the cakes until you are ready to bake and serve them. If you do, bring them back to room temperature before baking.
Place cakes in the oven and bake for 10 to 12 minutes (if you bake 6 cakes, they tend to need 10 minutes only). The less time you bake the cakes, the more gooey the inside will be. Remove from oven and leave them to rest for 5 minutes. Invert onto dessert plates or serve them in the ramekins. Dust with confectioners’ sugar before serving.
Notes
You will need: four ¾-cup ramekins or six 2/3-cup ramekins