A rich, moist chocolate cake for one baked in a 10-ounce ramekin with cocoa powder, heavy cream, and an egg white. A small chocolate cake, ready in 30 minutes.
Preheat the oven to 350°F (175°C) and lightly butter a 10-ounce ramekin.
In a medium bowl, whisk the melted butter, sugar, egg white, and vanilla until smooth.
In a small bowl, whisk the flour, cocoa powder, baking powder, and baking soda.
Stir the dry ingredients into the wet ingredients until almost combined. Pour in the heavy cream and stir just until the batter is smooth.
Pour the batter into the buttered ramekin.
Bake for 20 to 25 minutes, until the top is set, the edges pull slightly from the sides of the ramekin, and a toothpick inserted in the center comes out with a few moist crumbs.
Let the cake rest on a wire rack for 5 minutes before serving. Dust with powdered sugar.
Eat this cake straight from the ramekin with a spoon, or run a knife around the edges, place a plate on top, and flip it over to slide the cake out. Top it with powdered sugar, chocolate frosting, or homemade whipped cream.
Notes
Use a 10-ounce ramekin. Anything smaller and the batter overflows. Anything larger and the cake bakes flat and dries out at the edges.Spoon and level your flour. Spoon the flour into the dry measuring cup, then run a knife across the top to level it off. I never scoop directly from the bag. Scooping packs in too much flour, which is the most common reason a single serving cake bakes up dry.Don't overmix once the cream goes in. I stir just until the batter looks smooth. Overmixing develops gluten and the cake bakes up tough instead of tender.Pull it at moist crumbs, not a clean toothpick. I take this cake out when there are still a few crumbs clinging to the toothpick. The cake keeps cooking from residual heat in the ramekin and finishes moist instead of dry.Bloom the cocoa for deeper flavor. If you want a more intense chocolate flavor, whisk the cocoa powder into the warm melted butter before adding the rest of the wet ingredients. The heat releases more of the cocoa's flavor compounds.