1. Heat oven to 350°F. Grease 9-inch square baking pan.
2. Stir together apples, peanut butter chips, 3/4 cup sugar and 2 tablespoons flour in large bowl. Spread in prepared pan; dot with 2 tablespoons butter. Stir together remaining 1/4 cup sugar, remaining 1/2 cup flour, oats and cinnamon in medium bowl; cut in remaining 4 tablespoons butter until mixture resembles coarse crumbs. Sprinkle oat mixture over apples.
3. Bake 40 to 45 minutes or until apples are tender and edges are bubbly. Cool slightly. Serve warm with whipped cream, if desired. 6 to 8 servings.