Ingredients
- 1 tablespoon unsalted butter
- 1 tablespoon granulated sugar
- 1 tablespoon packed light brown sugar
- 1/8 teaspoon vanilla extract
- 1 egg yolk
- 3 tablespoons all-purpose flour
- 1 1/2 tablespoons semisweet chocolate chips plus more for topping
Instructions
- Place the unsalted butter in an 8-ounce microwave-safe mug. Microwave on high for about 30 seconds until the butter is fully melted.
- Stir in the granulated sugar, light brown sugar, and vanilla extract until the mixture is smooth. Add the egg yolk and mix until well combined. Stir in the all-purpose flour and the chocolate chips, then sprinkle additional chips on top.
- Microwave on high until the cookie puffs slightly and appears set, about 45 to 60 seconds. Let cool for about 1 minute before enjoying.
