In a large bowl, combine the flour, brown sugar and salt. Cut in butter until crumbly. Pat into a greased 9-in. square baking pan. Bake at 350° for 15 minutes or until lightly browned.
Meanwhile, drain the peaches and reserve juice in a small saucepan. Stir in the sugar and cornstarch until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from the heat; stir in peaches.
Pour into crust. For topping, combine the oats, brown sugar and flour. Cut in the butter until crumbly. Sprinkle over filling. Bake at 350° for 25-30 minutes or until golden brown and bubbly. Yield: 6-8 servings.