3/4 c. old fashioned rolled oats 3/4 c. firmly packed light brown sugar 1 tsp. cinnamon 1/2 tsp. salt 1/2 c. (1 stick) unsalted butter, cut into bits & softened 1 c. walnuts, toasted lightly, cooled & chopped 3 lb. Gravenstein or other tart apples, peeled & sliced 2 tbsp. fresh lemon juice 3 tbsp. [...]