Finely dice the merguez. Fry in a saucepan (or a large frying pan) with a splash of olive oil on medium to high temperature. When crunchy,  take out 1/3 and put aside to use as a topping in the end.

Meanwhile pound the fennel seeds in a mortar and finely dice the garlic clove. Halve the fennel bulb, remove the stalk and finely slice. Chop the fennel green and put aside for later use. Add garlic and pounded fennel seeds with another splash of olive oil to the merguez and fry for a minute. Add fennel and canned tomatoes, season with salt and pepper and let the sauce simmer on low temperature for about 20 - 25 minutes with a lid on.

Cook the pasta according to package instructions in salted water until al dente. Save some of the cooking water when draining the pasta. Add with pasta to the sauce. Season the pasta again if necessary. Serve sprinkled with fennel green and crunchy merguez.