6 large egg yolks
8 large egg whites
5 tablespoons unsalted butter (1 tablespoon softened, remaining butter cut into  ¼-inch chunks)
1 tablespoon granulated sugar, plus 1/3 cup
8 ounces semi-sweet chocolate (Scharffen Berger 62% cacao), coarsely chopped
1/8 teaspoon table salt
½ teaspoon vanilla extract
¼ teaspoon cream of tartar

Set oven rack to lower middle position, heat oven to 375° F. Take 1 tablespoon softened butter and rub it along the inside of four to six 8-ounce soufflé ramekins. . Next coat the inside with 1 tablespoon sugar; refrigerate until ready to use.

Melt the chocolate and the rest of the butter in medium bowl set over pan of simmering water. Once it’s melted take it off heat and stir in salt, vanilla, then set it aside.
Beat the yolks and remaining sugar with electric mixer set on medium until its thick and pale yellow, about 3 minutes. Add it into the chocolate mixture.

Beat whites with electric mixer set on medium speed until it looks foamy. Add cream of tartar and beat on high speed until you see stiff peaks. This mixture should be dense.

Stir in ¼ of whipped whites into chocolate mixture. Add in the remaining whites into mixture until it’s barely combined. Gently pour it into prepared dish.

Bake until the outside is set but inside is still a little loose and creamy. This should take 20-25 minutes. Serve immediately.