The two-slice portion on this summer pie is nice and hearty: For a lighter lunch or brunch for eight people, serve one slice with a simple spinach salad. For extra flavor, try tossing 2 teaspoons chopped fresh thyme into the crust.
Place quinoa on a jelly-roll pan. Bake at 350° for 10 minutes or until golden brown; cool. Place half of quinoa in a food processor; pulse 30 seconds. Transfer to a large bowl. Add remaining toasted quinoa, almond meal, cornstarch, and 1/4 teaspoon salt; stir to combine. Add 1 tablespoon oil and egg; stir until mixture is crumbly but holds together when pressed. Press into bottom and up sides of a 9-inch pie plate coated with cooking spray. Bake at 350° for 5 minutes.
Heat a medium skillet over medium-high heat. Add remaining 1 tablespoon oil to pan; swirl to coat. Add leeks; sauté 3 minutes. Add garlic; sauté 1 minute. Combine leek mixture, tomatoes, thyme, and remaining 1/2 teaspoon salt in a medium bowl; let stand 5 minutes. Add egg whites, stirring to combine.
Arrange tomato mixture in crust; sprinkle with cheese. Bake at 350° for 15 minutes or until filling is set. Let stand 10 minutes; cut into 8 wedges.