For the crust: Combine the flour, margarine, sugar, water and salt in a food processor and pulse until a smooth dough forms. Wrap in plastic wrap and refrigerate for 2 hours.
Preheat the oven to 325 degrees F.
Spray a 9-by-13-inch baking sheet with cooking spray and line the bottom with parchment.
Roll the dough out on a piece of parchment until 1/4-inch thick. Lift the paper and gently flip the dough onto the prepared baking sheet. Press the dough into the sides and bottom. Use a fork to poke holes all over the dough.
Bake until light golden brown, about 15 minutes. Allow to cool completely.
Lower the oven temperature to 300 degrees F.
For the lemon filling: Combine the sugar, lemon juice, tofu, cornstarch, flour, lemon extract, citric acid and turmeric in a blender and blend until smooth.
Pour the lemon mixture on top of the baked crust.
Bake until gently firm, about 30 minutes.
Allow the lemon bars to cool completely, then refrigerate overnight.
Run a knife along the sides of the baking sheet and then carefully lift the lemon bars out of the tray. Cut into 2 1/2-inch squares.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Richard Leach, Sweets By Chloe, New York, NY