Cut the onion into fine rings and sauté with the chopped garlic.
Cut the bacon into fine strips and cook with them. Then deglaze everything with the cream and bring to the boil. Add the parsley and parmesan and season with salt and pepper.
Before you pour the carbonara sauce over the spaghetti, add 1 egg yolk per person and stir well. You can also add parmesan over the sauce and spaghetti, if you like.