Sweeten this Valentine's Day with a giant sugar cookie cake. It has a layer of raspberry preserves and is topped with raspberry buttercream frosting for a fun and festive treat!
Preheat oven to 350°F. In the bowl of a stand mixer, cream together butter, vegetable oil, sugars, and egg. Meanwhile, sift together flour, cream of tartar, baking soda, and salt. Add dry ingredients to the wet ingredients, along with the vanilla, and mix until fully combined. Chill dough for 10-15 minutes.
Lightly grease a heart-shaped pan with either vegetable oil or cooking spray. Gently press the cookie dough evenly across the pan, creating an "edge" or "crust" around the edges. Bake for 16-18 minutes until edges are slightly golden brown. Let cool in pan for 10-15 minutes.
Turn the pan upside down and gently remove the cookie; set on a wire rack to cool completely before frosting. It is optional to remove the cookie from the pan, but recommended for serving purposes.
Frosting
Cream room temperature butter in the bowl of a stand mixer. Add vanilla extract, raspberry preserves, milk, and 1/2 cup powdered sugar. Stir slowly at first to combine. Continue adding remaining powdered sugar cup by cup, mixing in between additions until combined.
Assembly
Once the cookie is completely cooled, spread raspberry preserves evenly across the sugar cookie, leaving the "crust" as you would a pizza. Pipe or spread the buttercream frosting on top of the cookie cake.
Cut and serve. Store at room temperature for 1 day, or in the fridge for up to 2 days. Best if eaten within 24 hours of assembly.