Heat oven to 425 degrees and butter a 10-ounce ramekin. Dust the buttered ramekin with granulated sugar.
STEP 2
Combine the chocolate and 3 tablespoons butter in a heat-safe bowl set over simmering water. Cook, stirring occasionally, until melted and smooth.
STEP 3
In a medium bowl, combine 3 tablespoons sugar, egg, egg yolk, vanilla, and salt. Whisk until thick and pale, about 2 minutes. Whisk in flour until smooth.
STEP 4
Gently stir chocolate mixture into egg mixture.
STEP 5
Pour the mixture into the ramekin. Bake for 12 to 14 minutes until the edges are set and puffed, but the center is still soft.
STEP 6
Loosen the edges and invert onto a plate. Dust with confectioners’ sugar and serve with ice cream or whipped cream.