First dice the onions, tomatoes and garlic. Fry the onions in hot olive oil, then deglaze with a little red wine and simmer a little over low heat.
Meanwhile cook pasta al dente.
Then add tomatoes and garlic to the onions. Season to taste with a little salt and pepper. When the tomatoes are overcooked, add some chopped basil.
Place the pasta in deep plates, then pour a little tomato sauce over the pasta. Finally sprinkle everything with the grated Parmesan and serve decorated with a basil leaf.