For the bottom layer, mix flour, margarine and pecans; press into a 9x13 inch cake pan. Bake at 400° for about 13-14 minutes or until golden brown. Let cool.
Blend cream cheese and powdered sugar. Add half the Cool Whip and blend until smooth. Spread over the cooled crust layer. Refrigerate until firm.
In saucepan, combine sugar, corn starch, and gelatin. Add water and whisk over medium heat, cooking until mixture thickens. Continue cooking for about 3 minutes, stirring constantly.
Stir in almond extract. Add blueberries, blending well. Heat through briefly if you prefer crisp berries; if you prefer softer berries, cook an extra 2-3 minutes. Let cool.
Pour over other layers and refrigerate until firm. Top with remaining Cool Whip. Finish with a layer of toasted, chopped pecans.