Rinse the quinoa in a fine sieve under running water.
In a saucepan, combine the quinoa, vegetable broth, tomato passata, and lemon juice. Bring to a boil, then cover and simmer for about 20 minutes, stirring occasionally, until all the liquid is absorbed. If you have a rice cooker you can use it for this step.
Meanwhile, wash and trim the leek. Slice it into thin half-moons and rinse again if needed.
Heat the oil in a large pan and sauté the leek, stirring often, until soft and golden.
Add the dried herbs, then season with salt and pepper to taste.
Fluff the quinoa with a fork, then divide among plates and top with the golden leeks, or gently mix everything together before serving. Serve warm and enjoy.