• 1 to 2 tbsp. unsalted butter, softened, for molds
• 1 to 2 tbsp. granulated sugar, for molds
• 2 oz. good quality bittersweet chocolate, melted (1/2 c. if using chips or discs)
• 1/2 tsp. vanilla
• Optional add-ins (choose one): 1/4 tsp. cinnamon or 1/2 tsp. espresso powder or 1 tbsp. rum (or other liqueur)
• 2 eggs, room temperature, separated
• Pinch of salt
• 1/4 tsp. cream of tartar
• 1/4 c. plus 1 tbsp. granulated sugar
Preheat oven to 350 degrees (or wait until later; see below).
Using your fingers, thoroughly coat two 6- to 8-ounce baking dishes (ramekins, coffee mugs, anything deep and straight-sided) with butter. Pour 1 tablespoon of sugar into one dish, then cover with plastic wrap. Shake gently to generously coat all surfaces. Pour remaining sugar into second dish and repeat, adding more sugar if necessary.
Melt the chocolate in a medium metal bowl set over a small pot of barely simmering water. Stir occasionally until melted. Stir in vanilla and, if desired, an optional flavoring (cinnamon, espresso powder, rum or liqueur). Keep warm.
In a medium bowl, using an electric mixer, beat the egg whites with salt and cream of tartar until the whites hold soft peaks when the beaters are turned off and lifted. Continue to beat on high while gradually adding 1 tablespoon of sugar until the whites hold stiff peaks and look glossy. Don’t overbeat. Set aside.
In a small bowl, with the same beaters, beat together the egg yolks and 1/4 cup sugar on high speed until light-colored, thick and almost like frosting. This may take up to 5 minutes. With a spatula, gently fold egg mixture into the melted chocolate until few streaks remain (but a few are OK).
Stir a big dollop of the whites into the chocolate mixture to lighten it, then gently fold in the remaining whites with a spatula, lifting from the bottom and folding over the top until combined.
Divide batter evenly between the prepared dishes. You can bake them immediately, or cover with plastic wrap and hold in the refrigerator for up to 4 hours. When ready to bake, place the dishes on a baking sheet and place in the preheated oven for 18 minutes for a creamy center, 20 minutes for a firmer soufflé. Serve immediately with whipped cream, ice cream, or custard sauce and garnish with fresh berries.
Nutrition information per 8-ounce serving without garnish: