This was also in my mother's handwritten cookbook. I made it for the Jefferson County Fair on August 28, 2010 and it won 3 awards: 1) First Place, Champion, and Best in Show. I always make a double batch of this - it never lasts long!
For the bottom layer, beat the ingredients together using a mixer. It will be like a thick cake batter. Spray the pan lightly with PAM then pour the batter into an 8 or 9 inch pan. Using a spatula spread the batter to the edges of the pan.
For the top layer, place the blackberries on top of the batter in a single layer, covering the batter with the blackberries. Sprinkle the sugar over the blackberries, then pour 1 cup cold tap water on top.
Place on cookie sheet (sometimes it bubbles over) and place on center rack in oven.
Bake for 45 minutes to 1 hour; until the top is brown and the center doesn't jiggle. Cool before serving.
Serve with vanilla ice cream and/or whipped topping.
This same recipe may be used with apples, apricots, or canned peaches. It these fruits are used, place them on the bottom of a greased pan, batter on top, then sugar and water over all.
You may substitute boysenberries, huckleberries, or blueberries for the blackberries.