Preparation Preheat oven to 350°F. Line baking sheet with parchment paper. Mix flour, 3/4 cup Parmesan cheese, salt, garlic, and cayenne pepper in processor. Add butter and, using on/off turns, process until dough begins to come together. Gather dough into ball. Divide dough in half. Roll each half into 12-inch log, and cut each log into 1-inch pieces. Roll each piece into ball. Arrange dough balls on prepared baking sheet, spacing about 1 1/2 inches apart. Press each ball into 2-inch-diameter round. Sprinkle remaining 2 tablespoons Parmesan cheese over. Bake shortbread rounds until tops are dry and bottoms are golden brown, about 20 minutes. Transfer shortbread rounds to rack and cool completely. DO AHEAD: Shortbread rounds can be made 1 week ahead. Store rounds in airtight container at room temperature, or freeze up to 1 month.
Preparation Preheat oven to 350°F. Line baking sheet with parchment paper. Mix flour, 3/4 cup Parmesan cheese, salt, garlic, and cayenne pepper in processor. Add butter and, using on/off turns, process until dough begins to come together. Gather dough into ball. Divide dough in half. Roll each half into 12-inch log, and cut each log into 1-inch pieces. Roll each piece into ball. Arrange dough balls on prepared baking sheet, spacing about 1 1/2 inches apart. Press each ball into 2-inch-diameter round. Sprinkle remaining 2 tablespoons Parmesan cheese over. Bake shortbread rounds until tops are dry and bottoms are golden brown, about 20 minutes. Transfer shortbread rounds to rack and cool completely. DO AHEAD: Shortbread rounds can be made 1 week ahead. Store rounds in airtight container at room temperature, or freeze up to 1 month.