Instructions

1. Preheat oven to 350°F. Grease two standard size muffin cups with cooking spray or line with cupcake liners. Set aside.
2. In a small microwave-safe bowl, combine the butter and sugar. Microwave for 30 seconds, then remove and stir with a whisk. Repeat if the butter is not full melted
3. Add the egg yolk and vanilla extract. Whisk until the mixture lightens in color slightly.
4. Add in cocoa powder, flour, and salt and use a rubber spatula to fold together until no streaks of flour remain. If using chocolate chips, add the chocolate chips and fold to distribute.
5. Divide the mixture between your two prepared muffin cups and bake for roughly 16 t0 18 minutes. You’ll know they’re done when the edge is set, but a knife inserted into the middle still comes out with a bit of brownie batter on it.
6. Allow to cool slightly before eating!