Chocolate Chip Cookie Cake

INGREDIENTS

For the chocolate chip cookie base::

2 sticks

unsalted butter, melted

1/2 cup

granulated sugar

1 1/4 cups

lightly packed dark brown sugar

1 tbsp

milk

2 tsp

vanilla

large eggs plus 1 egg yolk, at room temperature

1 1/2 cups

all-purpose flour

1 1/4 cups

bread flour

1 tsp

baking soda

1 tsp

baking powder

1 tsp

cornstarch

1 tsp

fine sea salt

2 cups

semi sweet chocolate chips

For the buttercream::

1 1/2 cups

powdered sugar, sifted

4 oz

unsalted butter, at room temperature

fine salt

2 tsp

pure vanilla extract

1 tbsp

cream or milk

Sprinkles, for garnishing