Preheat oven to 350. Line an 8"X8" pan with foil.
Mix butter, flour, oats, sugar, brown sugar, and salt. Set 1 cup aside. Spread the remainder in the pan, smooth and hard pack.
Mix fruit, sugar, lemon juice and cornstarch. Said over the crust. Top with set aside mix.
Bake for about 55 minutes, edges are set and center is just set.
Cool for 30 minutes on a rack. Cut and serve.