6 tablespoons (3/4 stick) butter, softened to room temperature 1/2 cup sugar 1 1/2 teaspoons pure vanilla extract 1/2 cup all-purpose flour 2 egg whites
Preheat oven to 400° F. Grease four cookie sheets.
In a large bowl, cream butter and sugar together until light and fluffy. Add vanilla, then stir in flour.
In a separate bowl, beat egg whites until frothy. Blend into butter mixture.
Place four spoonfuls of dough on each of the four cookie sheets with a few inches of space in between. You should use up all the batter doing this; if you don't, distribute the remaining batter equally among the sixteen mounds. Place a plastic sheet or heavy plastic bag on top of each scoop of dough and roll out to thin circle 1/16 to 1/8 inch thickness, making sure the circles do not intersect.
Bake one sheet at a time for 5-6 minutes, or until edges are just barely colored. Remove from oven and quickly release each wafer from cookie sheet with a metal spatula.
Shape each into a cone by rolling with one end tighter than the other. As they cool, the cones will become hard.