2 quarts fresh or frozen blackberries. Add 1 to 1 1/2 cups of sugar depending on sweetness desires,
4-5 Tbs. corn starch, and 1 Tbs. lemon juice. Add some red food coloring for bright color. Bring to a slow boil over medium heat and check for sweetness and desired thickness. Top filling with a few slices of butter and bake @ 400* for 10 min. Reduce heat and back @ 350* for 25-30 min.
P.S. Coat crust with flour and sugar