1In large bowl, mix all filling ingredients. Let stand 30 minutes.
2Heat oven to 400°F. Spray 13x9-inch pan with cooking spray. Spoon apple mixture into pan.
3In medium bowl, mix 1 cup flour, the oats, 1/2 cup brown sugar and the ginger. Cut in 1/2 cup butter, using pastry blender (or pulling 2 table knives through ingredients in opposite directions), until mixture is crumbly. Stir in walnuts. Sprinkle evenly over apples.
4Bake 40 minutes or until apples are tender when pierced with fork and topping is golden brown. Serve with ice cream.