PREHEAT oven to 350°F if using a silver 9-inch springform pan (or to 325°F if using a dark nonstick 9-inch springform pan). Grease pan. Mix flour, oats and 3/4 cup sugar in large bowl; cut in butter until mixture resembles coarse crumbs. Reserve 1 cup crumb mixture. Add sour cream, 1 egg and baking soda to remaining crumb mixture; mix well. Spread onto bottom and 2 inches up side of pan.
BEAT cream cheese, remaining sugar and extract in small bowl with mixer until well blended. Add remaining egg; beat on low speed just until blended. Spoon into crust. Top with pie filling; sprinkle with reserved crumb mixture and nuts.
BAKE 50 to 55 min. or until top is golden brown. Cool 15 min. Run knife around rim of pan to loosen cake; remove rim. Serve cake warm or at room temperature. Refrigerate leftovers.