Cookie Cake:
3/4 cup salted butter, room temperature
3/4 cup dark brown sugar
1/4 cup sugar
1 egg
2 tsp vanilla extract
2 cups all purpose flour
2 tsp cornstarch
1 tsp baking soda
1 cup semi-sweet chocolate chips
12 oz bag peanut butter M&Ms (or similar size)

Vanilla Icing:
1/4 cup butter
1/4 cup shortening
2 cups powdered sugar
1/2 tsp vanilla extract
1-2 tbsp water
yellow and red icing color (or orange, if you have the right shade of orange)