Combine butter and sugar in the bowl of a stand mixer and beat until creamy. Add egg and vanilla extract and beat until combined

In a medium-sized bowl, whisk togetherflour, baking powder, and salt. Gradually add dry ingredients into wet until combined. Divide into 2 halves. Cover each with clear wrap and mold into 2 disks. Dough will be quite sticky at this point, thats OK!. Rrefrigerate for at least 2 hours. Preheat oven to 350F and line a baking sheet with parchment paper. Set aside. Flour a clean surface and roll out one disk. Lightly flour the dough and roll out to 1/8 (for thinner, crispier cookies) or 1/4 (for thicker, softer cookies). Add flour as needed both on top of and beneath the dough so that it doesnt stick. Use cookie cutters to cut out shapes and use a spatula to transfer shapes to prepared baking sheet. Bake on 350F for 9-10 minutess, or until edges just begin to turn lightly golden brown. Allow cookies to cool completely on cookie sheet before moving and frosting.

For Frosting: Combine sugar, 2 Tablespoons of milk, corn syrup, and vanilla extract in a medium-sized bowl and stir until combined. If too thick, add more milk, a teaspoon at a time, until the frosting is thick but pipeable. If you accidentally add too much milk, add powdered sugar until desired texture is reached. If coloring the frosting, divide into bowls and color as desired at this point. Transfer to a piping bag with a piping tip (I used Wilton 5). Pipe frosting on cookies and decorate with decorative candies, if desired. Allow frosting to harden before serving. Can take several hours. Use fan to speed drying. Keep in airtight container at room temperature.