Boil the pasta in plenty of salted water, following the instructions on the packet.
Steam the spinach for a couple of minutes until it starts to soften (if you don’t have a steamer, simply boil for a few minutes).
Gently fry the garlic in a frying pan with a little extra-virgin olive oil. When it is golden brown, remove and add the onion. Gently fry until it starts to caramelise and then add the mushrooms. Fry for 3 to 4 minutes together with the onion and then add the spinach at the end. Add salt and pepper.
Toast the pine nuts for a few minutes and then add to the frying pan. Stir well.
Mix everything together with the farfalle, add salt and pepper to taste and serve with some grated Parmesan cheese on top.