- 3/4 cup unsalted butter, at room temperature
- 1/2 cup sugar
- 1 tsp vanilla bean paste (or extract)
- 1/8 tsp salt
- 1 3/4 cups flour
- 6 oz semisweet chocolate, chopped
- 6 oz white chocolate, chopped
- Beat butter and sugar in a large mixer bowl at medium speed until combined; add vanilla bean paste and salt and beat until incorporated. Scrape down bowl as needed. Reduce speed to low and mix in flour just until incorporated and dough begins to come together in large pieces. Scrape dough out onto a piece of plastic wrap, shape into a disk and wrap well. Chill dough in the refrigerator until firm, about 30 minutes.
- Preheat oven to 350°F and line two baking sheets with silicone mats or parchment paper. Roll out dough to 1/4-inch thick on a lightly floured board. Use a floured 2-inch fluted biscuit cutter to cut out cookies. Gather scraps, re-roll, and cut until you have a total of 24 cookies. Place cookies on baking sheets and chill for 20 minutes in the refrigerator.
- Bake, rotating pans halfway through, for 14 to 15 minutes, until lightly golden and edges are set. Cool for 5 minutes on baking sheets, then transfer to a wire rack to cool completely.
- Line two jelly roll pans with parchment paper. Place semisweet chocolate in a double boiler or in a heat-proof bowl over a saucepan of gently simmering water. Slowly melt the chocolate, stirring occasionally until glossy and smooth. Dip one half of each cookie in melted chocolate and place on prepared pans. Chill cookies in the refrigerator for 15-20 minutes, until set. Repeat with white chocolate, slowly melting until glossy and smooth. Working quickly, dip the other half of each cookie in melted white chocolate and place back onto pans. Top with sprinkles, and chill again until chocolate is completely set, about 20 minutes. Store leftover cookies in a single layer at room temperature.