Start by heating a generous splash of olive oil in a large pan over medium-high heat.
Slice the casings on the sausages and squeeze the meat out directly into the pan, breaking it up with a wooden spoon or spatula.
Cook the sausage meat until golden and lightly caramelised, then remove it from the pan and set it aside.
Heat a little more oil in the same pan and add the fennel seeds, chopped garlic, fresh and dried chilli. Sauté for 1 – 2 minutes until fragrant.
Add the sliced onion and oregano leaves, then continue cooking for another 2 – 3 minutes until the onion softens slightly.
Squeeze in the juice of half a lemon, then return the cooked sausage mixture to the pan. Season with salt and pepper to taste.
Add the tinned tomatoes along with about ¼ cup of water, stirring everything together. Let this simmer for 5 – 6 minutes to deepen in flavour.
Pour in the thickened cream and continue to cook for another 3 – 4 minutes, allowing the sauce to become rich and slightly thickened.
Stir in the spinach and let it wilt gently into the sauce.
Finally, toss the sauce through cooked pasta, adding the grated parmesan, lemon zest, and a splash of pasta water if needed to loosen the sauce.
Serve with extra parmesan over the top.