In a microwave-safe mug or bowl, combine the cottage cheese and protein powder. Stir until they are well combined.

Add the unsweetened cocoa powder, almond flour (or oat flour), baking powder, sweetener, vanilla extract, and a pinch of salt to the mixture. Stir everything together until you have a smooth batter. If the batter is too thick, you can add a tablespoon of water or milk of your choice to reach your desired consistency.

If you'd like, you can fold in any optional add-ins like dark chocolate chips, chopped nuts, or dried fruits for extra flavor.

Microwave the mug or bowl on high for about 1 minute and 30 seconds to 2 minutes, or until the brownie has risen and set. Cooking time may vary depending on your microwave's wattage, so keep an eye on it to avoid overcooking.

Carefully remove the brownie from the microwave (it will be hot), let it cool for a minute, and then enjoy your single-serve protein brownie!