Preheat the oven to 350 degrees. Grease a 9x9-inch baking dish (or similar).
In a large bowl, toss the apples, lemon juice, sugar, and 2 tablespoons flour. Pour into the prepared baking dish.
In another mixing bowl, combine the oats, ½ cup flour, brown sugar, and salt. Add the SunButter and butter and work into the oat mixture until it reassembles coarse crumbs. Sprinkle the topping evenly over the apples.
Bake for 45 minutes or until the topping is golden brown and the filling is bubbly.
Serve warm with ice cream or whipped cream, if desired.