In a food processor, combine the flour and starch. Add the butter and pulse for a few seconds at a time until the butter is the size of peas. Add the egg and water and pulse again until the dough just begins to form. Add water, if needed. Remove the dough from the food processor and form into two discs. Cover and refrigerate for 30 minutes.
Roll out the dough between two sheets of parchment paper to about a 3 to 4-mm (1/8-inch) thick sheet. Line two 23-cm (9-inch) pie plates.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.