Tomato-zucchini filling

1 medium onion
1 tablespoon olive oil
3 or 4 Roma tomatoes
1 medium zucchini
¾ cup Gruyere cheese
Salt and pepper

Heat oven to 400 degrees F. Slice onions, tomatoes, and zucchini into rounds of ¼-inch thickness. Heat olive oil in a skillet and sauté onions until tender. Sprinkle tomatoes and zucchini with salt and pepper to taste. Place half the cheese on the bottom of the prepared pastry followed by a layer of cooked onions. Arrange the zucchini and tomatoes rounds decoratively in a circle. Top with cheese. Bake for 30 to 35 minutes until crust is golden brown.

Pastry

2¼ cups all-purpose flour
½ teaspoon salt
1 tablespoon sugar
10 tablespoons cold, unsalted butter, cut into ½-inch pieces
5 tablespoons cold butter-flavored shortening, cut into ½-inch pieces
1 egg
⅓ cup cold water

Combine flour, sugar, and salt in a large bowl. Using a pastry blender or two knives, cut the butter and shortening into the flour until mixture resembles coarse meal with large pea-size bits of butter and shortening. Refrigerate mixture for 10 minutes

Remove bowl from refrigerator. Whisk egg with water and sprinkle 3 tablespoons over dry ingredients. Stir with a large spoon and continue adding liquid one tablespoon at a time until dough begins to clump together. Form dough into two balls, flatten into disks, wrap in waxed paper or plastic wrap, and refrigerate for 30 minutes. (Freeze one round for future use).

On a lightly floured surface, roll out one round of dough until it is the desired size. Flip and rotate dough while rolling, so that it does not stick. If the dough cracks, pinch it together as needed. Place pastry in 8- or 9-inch tart pan with a removable bottom. Press dough into fluted side of tart pan and with a knife cut off excess dough to the height of tart pan.