Preheat oven to 375°.
To prepare filling, combine first 4 ingredients in a large bowl, tossing well. Spoon into an 8-inch square baking dish coated with cooking spray.
To prepare topping, lightly spoon flour into dry measuring cups; level with a knife. Place flour, oats, 2 tablespoons sugar, and salt in a food processor; pulse until just combined. Add butter; process until the mixture resembles coarse meal. Squeeze handfuls of topping to form large pieces; crumble evenly over filling. Bake at 375° for 40 minutes or until filling is bubbly and topping begins to brown.