In a food processor blend the walnuts, flour, and salt with the egg yolk, maple syrup and omega spread to form a breadcrumb consistency. Add the cold water and process to a dough. Place the dough in the refrigerator for 25 minutes. Roll the pastry out, line a lightly oiled flan dish, pierce it with a fork, and bake blind at 190 degrees Celsius for 10 minutes. Remove the foil and bake for a further 15 minutes.
Beat the egg whites until they are white and form peaks.
Combine the pumpkin, honey, vanilla and spices and process in food processor until smooth. Fold the mixture through the egg whites and fill the pastry shell. Bake in the oven for 40 minutes until the filling has set but is still soft.
Note: Omega spread is available from the refrigerated section of many healthy food stores. It's made with a blend of Omega 3 oils and contains no hydrogenated or trans fats.