2 tablespoons granulated sugar – for coating ramekins
2 tablespoons unsalted butter
2 tablespoons all-purpose flour
1 cup whole milk
6 ounces bittersweet chocolate – finely chopped
4 large eggs – separated into yolks and whites
0.5 cup granulated sugar – for custard and meringue
0.25 teaspoon fine salt
Instructions
Heat the oven to 400°F (200°C). Place a rack in the lower-middle position. Generously brush four 6-ounce ramekins with the softened butter using upward strokes, then coat the insides with the 2 tablespoons sugar, tapping out excess. Set the ramekins on a baking sheet.
Separate the 4 eggs, placing yolks in a small bowl and whites in a clean large mixing bowl. Let the whites stand at room temperature while you make the base.
In a medium saucepan over medium heat, melt the 2 tablespoons butter. Whisk in the flour and cook, whisking constantly, until foamy and no longer raw-smelling, about 1 minute.
Gradually whisk in the milk until smooth. Cook, whisking, until thick like pastry cream, 2–3 minutes. Remove from heat, add the chopped chocolate, and stir until fully melted and smooth.
Whisk the egg yolks into the warm chocolate base one at a time until glossy. Whisk in 2 tablespoons of the measured 0.5 cup sugar. Let the base cool until warm, not hot, about 5 minutes.
Add the salt to the egg whites. Beat with a hand mixer or stand mixer on medium speed to soft peaks, 1–2 minutes. Increase to medium-high and gradually rain in the remaining sugar; beat to glossy medium-stiff peaks, 2–3 minutes.
Stir one-third of the meringue into the chocolate base to lighten. Gently fold in the remaining meringue in two additions with a spatula just until no streaks remain.
Divide the batter among the prepared ramekins, filling to just below the rim. Level the tops with a spatula, then run your thumb around the inner rim of each ramekin to create a shallow moat.