Rinse the quinoa well in a fine sieve. Finely chop the onion and soften it in a saucepan with two tablespoons of olive oil, then add the quinoa and stir for a few minutes. Then add the tomato passata and a ladle of warm stock. Cook for 15 minutes adding more stock as it is absorbed.
In the meantime, peel the shrimp tails and cut the shrimp into pieces. Once the quinoa is cooked, add the shrimp, sprinkle with the parsley and a few basil leaves, and if needed a dash of stock. Stir to mix all the ingredients well and serve.