Best Cookie Cake Recipe - How to Make a Cookie Cake

Ingredients

• 1/2 c. (1 stick) butter, softened
• 3/4 c. packed brown sugar
• 1/4 c. granulated sugar
• 1 large egg
• 2 tsp. pure vanilla extract
• 1 1/2 c. all-purpose flour
• 1 tsp. baking soda
• 1/2 tsp. kosher salt
• 1 c. semi- sweet chocolate chips (plus more for sprinkling)
• 1/4 c. rainbow sprinkles (plus more for sprinkling)
• 1 c. vanilla frosting