In a small saucepan, combine sugar and cornstarch. Gradually stir in raspberries until blended. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Remove from the heat; stir in extract. Cool.
In a large bowl, combine the oats, flour, brown sugar, wheat flour, salt and vanilla. Cut in butter until mixture resembles coarse crumbs. Press 2-1/2 cups crumb mixture into a 9-in. square baking pan coated with cooking spray. Spread with cooled berry mixture. Sprinkle with remaining crumbs.
Bake at 350° for 25-30 minutes or until golden brown. Cool on a wire rack. Cut into bars.