Peel and dice the onions. Drain the tuna and chop it up. Cut the zucchini into small pieces.
Heat the olive oil in a pan and fry the onion cubes until translucent. Add the tuna and season with the spices. Deglaze with the milk and simmer for about 10 minutes.
Add the zucchini pieces and simmer for another 20 minutes.
Finally add the cream and simmer for another 5 minutes. If necessary, season again.