Peel and wash the potatoes and cook in salted water for about 20 minutes
Peel and chop the onion. Mix vinegar, 1-2 tbsp. water, salt, pepper and a little sugar, add 1 tsp. oil. Clean, wash and quarter the tomatoes. Clean, wash and pluck the rocket a little smaller. Mix all salad ingredients with the marinade
Peel the garlic. Cut half into slices. Wash the tuna and pat dry. Heat 1/2 tsp. oil in a coated pan. Fry the fish for 2-3 minutes on each side. Season with salt, pepper and lemon juice. Fry the garlic and lemon slices with the fish
Drain and mash the potatoes. Add milk and add the remaining garlic. Stir puree until smooth and season to taste. Serve everything