Beat at low speed until mixture is crumbly (2 to 3 minutes). Reserve 1 cup.
Press remaining crumb mixture on bottom of greased 13 x 9-inch baking pan.
Bake for 14 minutes.
Meanwhile, in 2 quart saucepan stir together sugar and cornstarch.
Add pineapple and lemon juice. Cook over medium heat, stirring constantly, until thickened (4 to 5 minutes). (Mixture will be very thick.) Spoon filling over baked crust; sprinkle with reserved crumbs.