Wash the spinach and boil them in salted boiling water for 5 minutes. Drain, squeeze and let them cool. Chop finely the onion and brown it in a pan with a drizzle of extra-virgin olive oil. When the onion is golden, add the bacon cut into strips and brown. Chop the spinach and pour them into the pan, add salt and pepper and cook over low heat for about 5 minutes. Add the ricotta and, if necessary, a few tablespoons of cooking water from the pasta and mix gently. Cook pasta in salted water until “al dente” and drain. Pour the pasta into the pan with the sauce, add the grated Parmesan cheese and cook. Serve hot with the addition of a sprinkling of Parmesan cheese and freshly ground black pepper.