Orange-Currant Shortbread Buttons

Preheat oven to 350 F.

In a large bowl, cream butter and powdered sugar together until light and fluffy. Stir in vanilla, salt, and orange zest, then blend in the flour. Add the currants and mix until combined.

Take about 1/2 tablespoonful sized scoops of dough and roll into balls, then flatten gently between your hands (buttons should be about 1/4 inch thick and an inch in diameter). Place on parchment paper or Silpat-lined baking sheets and prick them once in the center with a knife or skewer.

Sprinkle with granulated sugar, if using. Bake for about 12-15 minutes, or until the buttons are set and lightly golden around the edges. Remove from oven, let them cool completely and store in an airtight container.