Whole Wheat Pastry: In food processor, pulse together all-purpose and whole wheat flours, salt and pepper; pulse in butter and lard until mixture resembles coarse meal with some bigger chunks. Pulse in just enough water so dough holds together when pressed. (Or whisk dry ingredients together in bowl and, with 2 knives or pastry cutter, cut in butter and lard; stir in water.) Flatten into disc. Wrap and refrigerate for 30 minutes or for up to 1 day.

Remove sausage meat from casings. In nonstick skillet over medium-high heat, fry sausages, crumbling and stirring, until no longer pink. Add onions; sauté until lightly browned, 15 to 20 minutes. Scrape into bowl; mix in spinach and cheese.

In separate bowl, beat together eggs, cream, salt, pepper and nutmeg. Set aside.

On lightly floured surface, roll out dough into rectangle large enough to line bottom and sides of 13- x 9-inch/3.5 L metal cake pan plus 1/2-inch/1 cm overhang. Fold overhang down over edge and crimp. Line with parchment paper or foil and fill with pie weights or dried beans. Bake in centre of 400F/200C oven for 15 minutes. Remove weights and parchment; bake until crust is firm and dry to the touch, about 5 minutes.

Remove from oven; reduce heat to 375F/190C. Scatter sausage mixture over crust. Pour egg mixture over top. Bake in bottom third of oven until egg mixture is set and top is light golden, about 45 minutes. Let cool slightly in pan on rack. (Make-ahead: Let cool; refrigerate for up to 2 days.)

Makes 10 to 12 servings.