Halve, clean and wash the peppers. Dab dry well. Lightly oil a baking tray and place the bell peppers on it with the cut surfaces facing downwards. Grill under the hot oven grill for 3-5 minutes until the skin turns dark and blisters.
Put the pepper halves into freezer bags, close them tightly and let them cool down. Peel and finely dice the shallot. Wash oregano, dab dry, put some leaves aside for garnishing. Chop the rest finely.
Peel the skin off the peppers. Cut 5 red pepper halves into large pieces. Fry the shallot in hot oil. Add the bell peppers and oregano and steam briefly. Add vegetable juice and simmer for 5 minutes.
Cook spaghetti in boiling salted water for about 10 minutes. Cut the remaining peppers into small cubes. Remove from heat and puree the peppers in the juice. Add the diced peppers. Season sauce with vinegar, salt and pepper.
Drain the pasta and serve with the sauce. Garnish with remaining oregano and sprinkle with parmesan.