Preheat oven 300°F
1 cup butter
3 cups flour
1 cup very granulated sugar
Thoroughly cream butter and sugar. Add 2 ½ cups flour and mix. Turn out on a flour counter with the remaining ½ cup flour. Knead in remaining flour until dough cracks and does NOT stick to the counter. Roll ¼” thick; cut into 2×3 squares.
Bake on ungreased cookie sheet at 300°F for 20 minutes or until slightly brown.