Wash the vegetables and cut into bite-sized pieces. Dice the onion.
Heat the oil in a saucepan and fry the onion cubes until translucent. Add the canned tomatoes. Let simmer for a moment. Then add the vegetables and the crushed garlic. Season everything with salt and pepper. Cover and simmer for 15 minutes, stirring occasionally. Then stir in the grained cream cheese. Drain the water from the tuna and also fold the torn tuna into the vegetables. Let simmer for another 10 minutes at low temperature. Season to taste and pluck fresh basil into the pot as desired.
For a light meal, this dish can be served without a side dish. Otherwise rice or baguette is enough.