1-Minute Chocolate Peanut Butter Mug Cake

all-purpose flour 2 Tablespoons unsweetened cocoa powder 2 Tablespoons granulated sugar 1/4 teaspoon baking powder 1/4 cup milk 2 Tablespoons butter, melted 1 Tablespoon creamy peanut butter 1/4 teaspoon vanilla extract 1 Tablespoon mini chocolate chips