Blueberry Picnic Bars

Heat oven to 350 degrees. Line an 8" square baking pan with foil, letting ends extend above pan on 2 sides. In a large bowl, mix oats, flour, brown sugar, baking soda and salt. Add melted butter and stir with a fork until evenly moistened (mixture will be crumbly). Reserve 1/2 cup crumb mixture for topping. Press remaining mixture evenly and firmly over bottom of ungreased, foil-lined pan. Bake 12 min. to set crust. In a small saucepan stir berries, sugar, cornstarch and lemon juice over med. heat until simmering. Simmer, stirring occasionally, until juices are no longer cloudy, about 2 min. Spoon over crust. Crumble reserved crumb mixture over top. Bake for 30 min. Let cool completely in pan. Lift foil by ends onto a cutting board. Peel off foil; cut into 2" squares.