Cut the sausages into slices about 5 mm thick and fry them in a slightly higher large pan in a little oil. After frying, remove from the pan and keep warm. Heat the salted water for the pasta in a large pot.
Cut the onion into small cubes and fry in the pan until translucent. Add the finely diced bacon and sauté as well.
Add the spinach and heat. Add the garlic, broth and cream. Stir in the Parmesan cheese and season to taste with nutmeg, salt and pepper, simmer gently.
Put the tagliatelle in the boiling water, preheat the oven to 180°C. Grease a sufficiently large baking dish with a lid (I use a glass one) with a little butter.
Once the pasta is al dente, put about 1/3 of the pasta in the baking dish with a slotted spoon, spread 1/3 of the sausage, then 1/3 of the spinach mixture on top and sprinkle 1/3 of the grated Emmental on top. After two more passes, everything should be in the baking dish.
Put the lid on the baking dish and put the dish in the oven for about 20 minutes. Before serving with the lid open, be sure to let it cool a bit. It goes well with a colorful salad.