Preheat the oven to 375°F. Line a baking sheet with parchment paper or a silpat baking mat.
In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar until light, about 2-3 minutes.
1 cup salted butter, 3/4 cup granulated sugar
Add the egg, vanilla extract, and salt and beat again, scraping the sides and bottom of the bowl as needed.
1 large egg, 1 teaspoon vanilla or almond extract, 1/2 teaspoon salt
Add the flour and mix again on low speed just until combined. Divide the dough and color part of it with a few drops of gel food coloring, if desired.
2 1/4 cups all-purpose flour
Filled the cookie press with dough. Press the cookies onto the baking sheet about 1 inch apart, then sprinkle with coarse sanding sugar or sprinkles, if desired.
Sprinkles
Bake for 6-8 minutes, just until lightly golden around the edges. Transfer the cookies to a wire rack to cool.
If using the glaze, combine the ingredients in a bowl and whisk until smooth. Dip cooled cookies, then sprinkle with sprinkles, if desired and let them sit on a wire rack until the glaze has set.
1 cup powdered sugar, 1 Tablespoon milk, 1/4 teaspoon vanilla extract