Combine cocoa powder, flour, sugar, and salt in a microwave-safe coffee mug or Ramekins. Using a fork, stir until well combined. Add the milk, oil, and vanilla. Stir just until the dry ingredients are almost combined. Add the chocolate chips, and stir until well combined. Sprinkle a few more chocolate chips on top, if desired.

Place the mug in the microwave and microwave on high power for 1 minute. The brownie should have risen and still appear moist in spots on the top. Continue cooking in 10-second intervals if the batter still looks raw. Let the brownie cool for a few minutes before serving with ice cream.

#Notes:

Make sure to measure your flour correctly. If you add too much flour to the recipe, you will have a less dense and fudgy mug brownie. I highly recommend using a scale to measure your flour. However, if you don’t have a scale, be sure to fluff your flour with a spoon and then spoon it into your cups before leveling it off with a knife.

Do not overmix the batter, as it will lead to a tough brownie.
The center will continue to bake and set after you remove the mug from the microwave, so don’t worry if they seem a bit too soft and fudgy.