Grab a microwave-safe mug (about 12 ounces or larger). Add 4 tablespoons flour, 2 tablespoons sugar, 2 tablespoons cocoa powder, 1/4 teaspoon baking powder, and a pinch of salt. Stir to combine.

Pour in 3 tablespoons milk, 1.5 tablespoons oil (or melted butter), and 1/4 teaspoon vanilla. Mix until smooth, scraping the bottom and sides. The batter should be thick but pourable.

For extra gooey pockets, fold in 1 tablespoon chocolate chips. You can also add a small spoon of peanut butter or hazelnut spread in the center for a molten middle.

Microwave on HIGH for 50–70 seconds. Start checking at 50 seconds. The top should look set but still slightly glossy in the center. Avoid overcooking—it will continue to firm up as it rests.

Let it stand for 1 minute. Top with a small scoop of ice cream, a drizzle of cream, or a pinch of flaky sea salt. Eat warm with a spoon.