Ingredients

3/4 c. salted butter, softened

1 c. sugar

1 large egg

1 tsp. pure vanilla extract

2 tsp. vinegar

1 1/2 tbsp. red food coloring (less than 1 oz.)

2 1/4 c. plus 2 tbsp. all-purpose flour

2 tsp. cornstarch

1 tsp. baking soda

1 tbsp. cocoa powder

1/4 tsp. kosher salt

3 tbsp. sprinkles, plus more for garnish

4 oz. cream cheese, softened

3 tbsp. butter, softened

2 c. powdered sugar

1/2 tsp. pure vanilla extract

Preparation

Step 1Preheat oven to 350° and line a 9" cake pan with parchment. Grease all sides.Step 2In a large bowl using a hand mixer, cream butter and sugar until light and fluffy, 3 to 4 minutes. Add egg, vanilla, vinegar, and red food coloring and mix until well combined.Step 3In another medium bowl, whisk together flour, cornstarch, baking soda, cocoa powder, and salt, then add to wet ingredients and mix until combined.Step 4Stir in sprinkles and refrigerate cookie dough 30 minutes to 1 hour.Step 5Evenly press dough into cake pan. (It can be a little sticky so cover your fingers with parchment paper, if desired.)Step 6Bake until edges are firm, 18 to 20 minutes. Step 7Remove from oven and let cool completely in cake pan, then transfer to serving plate.Step 8Make frosting: Beat cream cheese and butter until smooth. Slowly add half the powdered sugar and mix until combined, then add vanilla and remaining powdered sugar and mix until smooth.Step 9Pipe frosting onto edges of cookie cake and garnish with more sprinkles. Store in an airtight container in the fridge until ready to serve.