1/2 cup powdered sugar
1 teaspoon almond flavoring
1 1/2 cups all-purpose flour
1/2 teaspoon salt
1/4 cup sugar
1/2 cup white baking chips or vanilla-flavored candy coating (almond bark)
1/4 cup roasted and salted shelled pistachio nuts, coarsely chopped
Combine butter and powdered sugar in bowl; beat at medium speed until creamy. Add egg and almond flavoring; continue beating until well mixed. Add flour and salt; beat at low speed until well mixed. Cover bowl with plastic food wrap; refrigerate 1 hour or until firm.
Heat oven to 350°F.
Place sugar into another bowl. Shape dough into 1-inch balls; roll in sugar. Place 2 inches apart onto ungreased cookie sheets. Flatten each cookie to 1/4-inch thickness, using bottom of drinking glass. If cookies stick to glass, dip bottom of glass in sugar. Bake 8-10 minutes or until lightly browned on bottom. Cool completely.
Place white baking chips into bowl. Microwave on Medium (50% power), stirring every 15 seconds, 30-60 seconds or until melted. Drizzle melted chips over cooled cookies. Immediately sprinkle each cookie with 1/4 to 1/2 teaspoon chopped pistachios. Let stand until drizzle is set.
To make ahead, bake cookies as directed. Cool completely. Place cooled cookies into freezer container with tight-fitting lid. Freeze up to 4 months. Let stand at room temperature until thawed. Drizzle with melted white baking chips; sprinkle with pistachios.