Rinse quinoa and drain. Cook quinoa in a lidded saucepan with stock: cover, bring to a boil, turn down to simmer for 15 minutes. Turn off heat and let sit for at least 30 minutes.

Mash cooked quinoa with rest of crust ingredients until well mixed and very sticky.

Lightly spray or oil a pie or tart pan.

Spread crust into the pan, using waxed paper to get the crust as even as possible.

Preheat oven to 350F/180C/gas mark 4.

Pre-bake crust for five minutes.

Heat a large nonstick skillet or cast iron frying pan over medium heat. Add oil and swirl to coat.

Sauté leeks and garlic for 10-20 minutes, reducing heat if necessary, until the leeks are soft, wilted, and golden brown.

While leeks are cooking, thinly slice or chop tomatoes, removing all the seeds and goo. Put tomatoes in a colander and sprinkle lightly with salt. Let sit for at least 10 minutes; 30 is better. The salt draws out moisture, resulting in a better filling.

Pat the tomatoes as dry as possible with a clean kitchen towel or paper towels.

Whisk together the eggs, coconut milk, and thyme. Add 5-6 grinds of cracked black pepper and remaining salt (about 1/8 tsp). If using cheese, mix half in now.

Stir in the tomatoes and the leek mixture. Pour filling into crust. Sprinkle with cheese if using.

If making a tomato rainbow, reserve tomatoes until filling is in crust, then arrange on top of filling, pressing in. Sprinkle with remaining cheese if using.

Bake for 35-40 minutes, checking after 30. Crust should be light brown, filling completely set (no jiggling), and golden brown. Let cool on a rack for at least 10 minutes before cutting.