Preheat oven to 350°F.

Coat a springform pan with non-stick cooking spray and set aside.

Using a standing mixer, cream together the butter and sugar until light and fluffy.

Add the egg, egg yolk, and vanilla extract and continue mixing until fully incorporated.

In a separate mixing bowl, whisk together flour, salt, baking powder, baking soda and cornstarch.

Gradually mix dry ingredients into bowl of wet ingredients. Continue mixing until you have a dough consistency.

Stir in candy and sprinkles by hand.

Using a rubber spatula, press the dough into the springform pan

Bake ay 350°F for 20-25 minutes or until the cookie is light golden brown on top.

Remove from oven and allow to cool completely before frosting.

Using a standing mixer, combine the butter, powder sugar, vanilla, and heavy whipping cream. Mix the frosting until fully combined and stiff peaks form.

Scoop frosting into a plastic piping bag fitted with a star tip.

Carefully remove the cookie cake from the springform pan and place onto a serving plate.

Pipe the frosting around the edge of the cookie cake and top with pastel sprinkles.