Combine powdered sugar and vanilla bean, stirring well. Cover and let stand 24 hours.
Combine flour, almonds, sugar, and vanilla extract in a medium mixing bowl; cut in butter with a pastry blender until mixture resembles coarse meal. Sprinkle cold water, 1 tablespoon at a time, evenly over surface; stir with a fork until dry ingredients are moistened. Shape dough into a ball; chill at least 45 minutes.
Divide dough into 1-inch balls; shape each ball into a crescent-shaped cookie. Place on ungreased baking sheets. Bake at 350° for 15 minutes or until lightly browned. Cool on wire racks. Roll cookies in reserved powdered sugar mixture.
Oxmoor House Homestyle Recipes