Grease a microwave-safe mug or bowl
Mix 4 tbsp flour, 2 tbsp sugar, 2 tbsp cocoa powder, and a pinch of baking powder
Add 3 tbsp milk, 2 tbsp oil, and 1/4 tsp vanilla extract
Stir until smooth and lump-free
Pour the batter into the prepared mug or bowl
Microwave on high for 60 to 90 seconds
Check if the cake is set in the center
Microwave in 10-second intervals if needed
Let it cool for 1 to 2 minutes
Remove carefully and serve