In a small bowl, combine 2 tablespoons creamy peanut butter, 1 tablespoon granulated sugar, and 1 tablespoon brown sugar. Mix well until smooth.
Add 1 tablespoon all-purpose flour and 1/8 teaspoon baking soda to the peanut butter mixture. Stir until fully incorporated.
Add 1/8 teaspoon vanilla extract and 1 tablespoon beaten egg to the mixture and stir until a dough forms.
Line a microwave-safe plate with parchment paper or lightly grease it.
Scoop the dough onto the prepared plate and flatten it gently into a cookie shape about 3 inches in diameter.
Microwave on high for 45 to 60 seconds until the cookie is set but still soft in the center.
Allow the cookie to cool for 2 minutes before eating, as it will firm up slightly.