In a mixing bowl, cream shortening and brown sugar. Combine the flour, oats and salt; gradually add to creamed mixture. Press dough into a greased 13-in. x 9-in. x 2-in. baking dish. bake at 350 degrees F for 15-18 minutes or until golden brown. Spread with jam.
For filling, beat the cream cheese, sugar and flour until fluffy. Add the eggs, lemon juice and peel just until blended. Carefully spoon over jam. Bake at 350 degrees F for 30-35 minutes or until center is almost set. Cool on a wire rack. Cover and store in the refrigerator.