4 c. fresh blackberries or 2 (16 oz.) pkgs. frozen blackberries
3 tbsp. lemon juice
2 tbsp. cornstarch
25 vanilla wafers, coarsely broken
1/2 c. reg. oats, uncooked
1/2 c. packed brown sugar
2 tbsp. all-purpose flour
1 tsp. ground cinnamon
1/4 c. butter, melted
Whipped cream or ice cream (optional)

Place berries in lightly greased 11 x 7 x 2-inch baking dish. Combine lemon juice and cornstarch; pour over berries and bake at 425 degrees for 15 minutes. Combine wafers, oats, sugar, flour and cinnamon; add butter and stir until mixture resembles coarse crumbs. Sprinkle over hot berries. Reduce heat to 375 degrees and bake 20 minutes longer or until topping is crisp. Serve with whipped cream or ice cream if desired. 6 to 8 servings.