Christmas Tree Sugar Cookies

1. Preheat oven to 350º F.
2. In a stand mixer fitted with a paddle attachment, blend together the butter and sugar on medium speed until light and fluffy. Scrape down the sides of the bowl.
3. Add in the egg and vanilla and mix until combined.
4. With the mixer on low, sift in the flour, cornstarch, and salt and mix just until combined, scraping down the sides of the bowl as needed.
5. Flatten the dough into a disk and wrap in plastic wrap. Chill for 30 minutes.
6. Place a piece of parchment or a dough mat down and lightly flour it. Place the chilled dough on top, sprinkle some flour over it and roll it out until it is about ¼" thick. Sprinkle a little more flour where needed as you roll it out, making sure it isn't sticking to the parchment or mat that's under it.
7. Once the dough is rolled out, slide a cookie sheet under the mat or parchment and place it in the freezer for a few minutes or the fridge for 10 minutes. This will help firm up the dough again before you cut out any shapes.
8. Use a tree cookie cutter to cut out trees and gently transfer them to a parchment lined baking sheet. Reroll the dough as needed to cut out more. Bake for 8-10 minutes depending on the cookie size. Let cookies cool for 10 minutes before moving to a cooling rack.

Vanilla Buttercream

1. Cream the butter until smooth.
2. With the mixer on low, slowly add in the confectioners sugar by the spoonful followed by the vanilla and cream.
3. Scrape down the sides of the bowl and mix just until combined.

Assembly

1. Place each cookie on a piece of parchment as you frost it. Transfer buttercream to a pastry bag with a Wilton #8 or similar piping tip. Starting at the top left side of the tree, pipe a diagonal line and continue that line down, alternating from one side to the other.
2. Sprinkle rainbow sanding sugar over the frosting until the frosting is fully covered. Carefully shake the excess sugar off of the cookie and onto the parchment. Use the parchment to transfer the leftover sugar to a small bowl and use again. Repeat this process with the remaining cookies. Enjoy!