Cook the spaghetti in boiling salted water for 12-15 minutes. In the meantime, clean, wash and chop the spring onions. Heat the oil in a pan and fry the spring onions for 2-3 minutes. Stir the sauce powder into 1/4 litre cold water. Add to the spring onions and bring to the boil while stirring. Let it boil for about 1 minute at low heat.
Drain the tuna, chop it up a little and stir it into the sauce with the olives. Season to taste with salt and pepper. Wash the thyme, dab dry, remove leaves, except for a few for garnishing, pluck from the stalk and sprinkle over the sauce. Drain spaghetti and let it drain. Arrange on plates with sauce and serve garnished with remaining thyme