Recipe for Sand Tarts

From Grandmother Rogers recipe box, an English treat:

INGREDIENTS:
1 cup soft butter or margarine
2 cups sugar
2 eggs, separated (leave egg whites to glaze tops)
1 teaspoon baking powder
3 cups sifted all-purpose flour
Powdered cinammon
Sugar

PREPARATION:
Cream butter and sugar. Add egg yolks and beat until light. Add sifted dry ingredients and mix well. Chill dough for at least 3 hours.
On a lightly floured surface, roll dough very thin and cut to desired shape.
Put on greased cookie sheets, brush with unbeaten egg whites, and sprinkle with sugar and cinnamon.
Bake in 375° oven for about 8 minutes.

GRANDMA'S NOTE: "These are difficult to handle. I make quite small as they are expensive.