Combine flour, oatmeal, fructose, and baking soda in a large mixing bowl; stir to mix.
Cut in the margarine until mixture is coarse crumbs.
Remove 1/2 cup (125 mL) and set aside.
Press remaining crumbs into an ungreased 9 in. (23 cm) shiny baking pan.
Combine cold water and cornstarch in a small saucepan.
Stir to blend.
Add raisins and orange peel.
Stir and cook over medium heat until mixture is thick and bubbly.
Spread over crumb layer in baking pan.
Sprinkle reserved crumbs over raisin mixture.
Lightly press top crumbs into raisin layer.
Bake at 350°F (175°C) for 30 minutes.
Cool in pan on a cooling rack.
Cut into 25 squares.