Preheat oven to 325 degrees F. Line large cookie sheets with parchment paper or foil. Lightly grease foil, if using. In a food processor combine 1 cup almonds and the powdered sugar. Cover and process until finely ground. Set aside.
In a large bowl, beat the egg whites, amaretto, and cream of tartar with an electric mixer on high speed until soft peaks form (tips curl). Gradually beat in 1/2 cup granulated sugar, about 1 tablespoon at a time, until stiff peaks form (tips stand straight). Fold half of the almond mixture into the egg egg white mixture. Fold in remaining almond mixture.
Spoon almond mixture into 1-inch diameter mounds, 2 inches apart on the prepared cookie sheets. Place a whole almond atop each cookie. Sprinkle lightly with coarse sugar.
Bake for 13 to 15 minutes or until tops are set and lightly browned. Cool completely on cookie sheets on wire racks. Peel cookies off parchment paper or foil when cool. Makes about 48 cookies.