Preheat oven to 400°F. Spray 6 (4‑ounce) ramekins or custard cups with nonstick spray.

Sprinkle 2 tablespoons of granulated sugar into a ramekin, turning to coat the bottom and side evenly. Pour the excess sugar into a second ramekin to coat. Repeat with the remaining ramekins. Spoon 1 teaspoon of the fruit spread in the bottom of each ramekin. Whisk together 1/2 cup of the granulated sugar, cocoa powder, cornstarch, espresso powder, and salt in a medium saucepan. Whisk in milk and set over medium heat. Cook, stirring constantly, until mixture thickens and begins to boil, about 3 minutes.

Put the chopped chocolate in a medium bowl. Pour the hot milk mixture over the chocolate, stirring until chocolate is melted and smooth. Stir in egg yolk and vanilla. Let cool 15 minutes.

With an electric mixer on medium speed, beat egg whites and cream of tartar in a large bowl until soft peaks form. Add remaining 1/4 cup granulated sugar, 1 tablespoon at a time, beating until stiff, glossy peaks form. With a rubber spatula, stir about 1/4 of the beaten egg whites into the chocolate mixture to lighten it. Gently fold in remaining egg whites just until no streaks of white remain.

Spoon the chocolate mixture into the ramekins, filling each about 3/4 full. Place the dishes in a large shallow baking pan. Put the pan in the oven; add enough hot water to come halfway up the sides of the dishes. Bake until puffed and golden, 20 ‑ 25 minutes. Remove the soufflés from the water bath. Lightly dust with confectioners’ sugar and serve at once.