1. In a large pot of salted boiling water, cook the spaghetti (following the cooking time indicated on the package). Drain them without cooling them down and keep 25 cl of cooking water. In the pot used to cook the spaghetti, add the cooking water, the spaghetti, and the vegetable spaghetti. Gently mix, add a tablespoon of olive oil, check the seasoning, transfer to a serving bowl, and serve.