Boil up plenty of salted water. Sort the spinach, wash and drain. Peel and chop onion and garlic. Cut bacon into pieces. Cook pasta in salted water according to package instructions.
Fry bacon in a hot coated pan until crispy, remove. Fry onion and garlic in hot butter. Sprinkle with flour and sauté lightly. Stir in milk and cream, bring to the boil.
Season with salt and pepper and simmer for 1-2 minutes.
Add the ricotta to the sauce and melt while stirring. Add the spinach and let it collapse. Finally fold in bacon. Season the sauce with salt and pepper. Drain the pasta and mix with the ricotta and spinach sauce, serve.