Almond Shortbread Cookies

Makes 8.
6 tablespoons (3/4 stick) chilled unsalted butter, cut into 8 pieces
1/4 cup (packed) golden brown sugar
3/4 teaspoon vanilla extract
Pinch of salt
3/4 cup tapioca flour
1 tablespoon arrowroot
1/4 cup sliced almonds (about 1 ounce)

Preheat oven to 375°F.

Place 9-inch-diameter metal pie pan in freezer to chill. Combine butter, brown sugar, vanilla and salt in processor. Blend until smooth, about 20 seconds. Add flour and arrowroot. Using on/off turns, process until dough clumps together. Press dough evenly onto bottom of chilled pie pan. Sprinkle almonds over dough, press almonds lightly into dough to adhere. Freeze until chilled, about 5 minutes.

Bake shortbread until edges are golden brown, about 22 minutes. Transfer pan to rack. Cut warm shortbread into 8 wedges; cool completely in pan.

(Can be prepared 1 day ahead. Cover; store at room temperature.)