How to Make It
Preheat the oven to 350 degrees. Line 2 baking pans with parchment paper and set aside.
Beat the butter, sugar, and vanilla with an electric mixer until light and fluffy, about 3 minutes. Add flour and salt and beat until just combined. Using a 1½-inch cookie scoop, scoop and roll 24 balls, dipping them in sugar, if desired, and arrange on the prepared pans, 2 inches apart.
Press a piece of gelt into the top of each cookie, flattening slightly. Bake until the edges of the cookies are golden, 10 to 12 minutes. Let cool on baking sheet pans for 15 minutes; transfer to a cooking rack to cool completely.