Preheat oven to 350°F. For the Filling, toss apple and pear slices with lemon juice and vanilla in large bowl. Mix cornstarch and 2 teaspoons cinnamon in small bowl. Sprinkle over fruit; toss to coat well. Spoon into 11x7-inch baking dish sprayed with no stick cooking spray.
For the Topping, mix brown sugar, flour, oats and 1 teaspoon cinnamon in medium bowl. Cut in butter with pastry blender or 2 knives until coarse crumbs form. Sprinkle evenly over fruit.
Bake 40 to 45 minutes or until fruit is tender and topping is golden brown.