Peel and dice the potatoes and cook in the stock for about 20 minutes. In the meantime cut the tomatoes in half. Cut onions into rings. Cut lettuce into bite-sized pieces. Pluck basil leaves
Mix the prepared ingredients and arrange in portions on plates. Slice parmesan cheese from the piece over it. Mash the potatoes finely in the broth. Press garlic through a garlic press. Stir into the potato sauce with vinegar and oil. Season to taste with salt, pepper and sugar. Serve potato vinaigrette with salad