Valentine's Slice-and-Bake Cinnamon Heart Shortbread Cookies

Beat butter in a large bowl with a hand mixer until fluffy; add vanilla extract, confectioners' sugar, ground cinnamon candies, and cornstarch and mix with hand mixer until combined.

Incorporate flour 1/4 cup at a time, mixing with your hands until all flour is used and dough comes together.

Divide dough into halves; roll each into an 8-inch cylinder. Wrap each cylinder in waxed paper and freeze until firm, at least 1 hour to overnight.

Preheat oven to 350 degrees F (175 degrees C). Remove dough from freezer and let thaw just until slightly softened.

Cut dough into 1/4-inch slices and arrange onto baking sheets.

Bake in preheated oven until firm along the edges but not yet browned, about 10 minutes. Cool cookies on racks for 5 minutes before moving to a rack to cool completely.