Scratch tomatoes crosswise, place briefly in boiling water, rinse cold, peel skin. Cut tomatoes into quarters, remove seeds and dice. Peel carrots and cut into pieces. Wash, clean and dice the zucchini. Quarter peppers, remove seeds, wash and cut into cubes.
Peel onion and garlic. Cut onion into strips, chop garlic finely. Heat oil in a pot. Steam vegetables for about 3 minutes. Add vegetable stock and tomato puree and cook for about 10 minutes. Season to taste with salt and pepper. Wash oregano, dab dry and chop finely, except for a little bit for garnishing. Stir into the soup. Arrange minestrone on a plate.
Add vegetable stock and tomato puree and cook for about 10 minutes. Season to taste with salt and pepper. Wash oregano, dab dry and chop finely, except for a little bit for garnishing. Stir into the soup. Arrange minestrone on a plate. Sprinkle with parmesan slices and garnish with oregano leaves