Preheat oven to 350°F (177°C). Spray a 9-inch pie dish or 9-inch round cake pan with nonstick spray. Set aside.

In a large bowl using a handheld mixer or stand mixer fitted with a paddle attachment, cream the softened butter for about 1 minute on medium speed. Get it nice and smooth, then add the sugar on medium speed until fluffy and light in color. Beat in egg, egg yolk, and vanilla. Scrape down the sides as needed.

In a medium bowl, whisk together the flour, salt, baking powder, baking soda, and cornstarch. With the mixer running on low speed, slowly add the dry ingredients to the wet ingredients in 3 different parts. The dough is quite thick. Once combined, gently fold in the white chocolate chips and 1/2 cup sprinkles using a rubber spatula (or by mixing on low speed).

Press the cookie dough evenly into the prepared pan. Bake for 25-30 minutes or until very lightly browned on top. You want the cookie cake to be extra soft in the center, so careful not to overbake. Allow the cake to cool completely on a wire rack at room temperature before frosting. The center will slightly sink—that’s normal.

With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy—about 2 minutes. Add confectioners’ sugar, cream, vanilla and almond extracts with the mixer running on low. Increase to high speed and beat for 3 full minutes. Add more confectioners’ sugar if frosting is too thin or more cream if frosting is too thick. Add a pinch of salt if frosting is too sweet. I usually add anywhere between 1/8 – 1/4 teaspoon of salt.

Frost the cake as desired, I used a Wilton 1M piping tip to decorate the edges. Using a very sharp knife, cut into slices and serve. This cake goes wonderfully with vanilla ice cream! Store cake in an airtight container at room temperature for up to 2 days and in the refrigerator up to 5.