Blueberries are in season for about six months. When you crave them, and they're not available fresh, count on frozen to make to these luscious bars.
Line an 8x8x2-inch baking pan with foil; set aside.
In a medium mixing bowl combine oats, flour, and brown sugar. Cut in butter until pieces are size of small peas. Reserve 1 cup of the mixture. Press remaining oat mixture into the bottom of prepared pan. Bake in a 350 oven for 25 minutes.
In a medium mixing bowl combine frozen blueberries, preserves, and lemon peel. Carefully spread over baked crust. Sprinkle with reserved oat mixture, pressing lightly into blueberry mixture.
Bake for 30 minutes more or until top is golden. Cool completely in pan on a wire rack. Cut into bars.