Cut the sausages open, then remove the sausage meat from the casings.
Heat some cooking oil in a large frying pan over a medium to high heat. Add the sausage meat, then use a wooden spoon or a spatula to break it up into small pieces.
Keep cooking, stirring often, until it starts to turn a nice golden brown.
Once goldened, add the grated onion, fennel seeds, and garlic. Cook for a couple more minutes.
Pour in the tin of tomatoes and the milk, then stir it well. Turn the heat down to a medium and simmer for about ten minutes.
Meanwhile, cook the pasta in salted boiling water for 2 minutes less than the packet states.
Once the pasta is cooked, drain it but keep some of the pasta water.
Add the pasta into the ragu, along with some pasta water, and grated parmesan. Stir well and add more pasta water if it seems to dry.
Taste for seasoning, then dish it up and finish it with some more grated parmesan cheese. I added a little parsley on top just for aesthetic purposes.