From 1922:
Put one lb. stoned dates, one cupful granulated sugar and half cupful cold water into a saucepan, and boil until the dates are soft. Allow to cool. Cream together one cupful each brown sugar and butter, add two and a half cupfuls rolled oats, and two and a half cupfuls flour. Mix well, add half cupful hot water and one teaspoonful baking powder and divide into two parts, roll the mixture out thinly, spread dates on one-piece, and place other over it. Cut into squares and bake in a hot oven.