Chocolate Chip Cookie Dough Mug Cake. Tempted to make one tonight! ... Crack egg into mug. Add 3 Tbsp brown sugar, 1/3 cup of flour, 1 Tbsp of softened butter. Top w/ 3-4 Tbsp of mini chocolate chips. Mix with spoon. Microwave for 1.5 minutes, or until top center of cake has set. Serve w/ dollop of ice cream.