This chocolate mug cake is quick, rich, and perfectly soft in the center. Made in the microwave with simple pantry ingredients, it comes together in minutes with melted chocolate tucked inside every bite.
In a microwave-safe mug, mix 3 tbsp all-purpose flour, 11½ tbsp granulated sugar, ½ tsp baking powder, and 1 tbsp unsweetened cocoa powder until evenly combined. Add 5 tbsp whole milk and 1½ tbsp vegetable oil, then stir until the batter is smooth and lump-free.
Press 3-4 pieces dark chocolate into the center of the batter.
Microwave the chocolate mug cake on high for 1 minute 20 seconds to 1 minute 40 seconds, until the cake has risen and the top looks set.
Let the mug cake cool for 1–2 minutes before serving warm.
Notes
Mix the Batter Well: Stir right to the bottom of the mug because I find dry flour pockets can easily hide there. Check Early: I usually start checking the mug cake at 1 minute 20 seconds since microwaves can cook very differently. Keep the Chocolate in the Center: Pressing the chocolate into the middle helps create a softer, gooier center once the cake cooks. Let It Rest Briefly: The texture becomes softer and more balanced if you let the mug cake sit for 1–2 minutes before eating.