Step 1: Make the cookie dough

1. Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
2. In a large bowl, beat the softened butter and powdered sugar with a hand or stand mixer on medium speed until light and fluffy, about 2 minutes.
3. Mix in the vanilla extract until combined.
4. In a separate bowl, whisk together the flour, cornstarch, and salt. Gradually add the dry ingredients to the wet mixture, mixing on low speed until a soft dough forms.

Step 2: Shape the cookies

1. Roll tablespoon-sized portions of dough into balls and place them on the prepared baking sheets, spacing them about 1.5 inches apart.
2. Flatten each ball slightly with the bottom of a glass or your palm.

Step 3: Bake the cookies

1. Bake in the preheated oven for 10-12 minutes, or until the edges are set but not browned.
2. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Step 4: Make the icing

1. In a small bowl, whisk together the powdered sugar, milk (or cream), and vanilla or almond extract until smooth. Add more milk, 1 teaspoon at a time, if the icing is too thick.
2. Divide the icing into separate bowls and tint with food coloring as desired.

Step 5: Decorate the cookies

1. Spread or drizzle the icing over the cooled cookies.
2. Add holiday sprinkles, edible glitter, or other festive decorations before the icing sets.

Step 6: Serve and store

1. Let the icing harden for about 30 minutes before serving or storing. Store cookies in an airtight container at room temperature for up to 1 week.