Combine flour and salt in a mixing bowl. Cut in the butter and shortening with a pastry blender or a fork. Add about 5 tablespoons of cold water until you can form the dough into a ball. Roll it out to fit a 9-inch deep-dish pie plate.
Heat oven to 375 degrees F. Spread the walnuts in the unbaked pie shell. In a mixing bowl combine all remaining ingredients and blend with a whisk until smooth. Pour the filling over the walnuts. Bake for 35 to 40 minutes, until firm.