Combine cheese and butter; mix well. Add flour, mixing well. Chill at least 1 hour.
Roll dough to 1/2-inch thickness; cut with a 1 1/2-inch biscuit cutter. Place on ungreased baking sheets. Top each with a pecan half. Bake at 450° for 10 minutes or until lightly browned. Place on wire racks to cool. Sprinkle with powdered sugar.