Mix the dry ingredients (flour, sugar, cocoa powder, and baking soda) in one bowl and the wet ingredients (milk, oil,) in another. Pour the milk mixture into the flour mixture, then stir until smooth.

Prepare a muffin tin with muffin liners. Fill the liners about ¾ full.

Bake in a preheated oven until a toothpick inserted into the center comes out clean. Cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.