We've been in love with this dish ever since we had it as an appetizer at Lupa in Manhattan. Lupa is a former Mario Batali joint, and is now run by Mark Ladner (who you might recognize as one of Mario's sous chefs on Iron Chef America).
The basis for the ragu is Mario's basic tomato sauce. We use this sauce a lot as it is very versatile. We always make a good sized batch, divvy it up into 1- and 2-cup portions and keep it in the freezer.
The fennel part of the sauce comes from both fresh and dried fennel.
The fresh fennel bulb gets finely chopped up, and the dried fennel seeds get toasted and ground. Both are sauted along with some red onion, carrot, celery, garlic, red chile flakes and sweet Italian sausage removed from its casing and broken up. The ragu comes together after a long simmer with the basic tomato sauce.
The gnocchi start with ricotta cheese that has been drained overnight. Mario's recipe calls for goat-milk ricotta, which is great if you can get it, but standard cow's milk ricotta works for us.
After adding a bit of flour and egg you form football shaped quenelles with a pair of spoons. The dough is light and moist, but fairly easy to work with.
The gnocchi only take a few minutes to cook. They sink initially and are nearly done once they float to the surface.
Perfect versions are delicate, with an almost velvety texture when you bite into them. Their simple seasoning of salt, pepper and a touch of nutmeg is a nice counterpoint to the aggressively flavored fennel and sausage sauce.
The Lupa recipe can be found here, but we use the Molto Mario version of the recipe and add double the tomato sauce to loosen the ragu a bit. Note that this recipe make a *lot* of sauce. We generally make a half batch of the ragu and still have some leftover (which isn't a problem -- it's great as a pasta sauce).