Preheat the oven to 180ºC/gas 4.Peel and finely slice the onion, peel and chop the garlic, then dice the chilli.Fry the onion in a large pan in a lug of oil for 5 minutes, or until softened.Add the garlic, chilli and lemon zest, then fry for a couple of minutes. Chop and add the sausages, then cook for 10 minutes until turning golden.Meanwhile, cook the pasta according to the packet directions until al dente. Drain, then toss with 1 tablespoon of oil and pour into a baking dish.Tear the kale into the pan, then pick, chop and stir in the oregano. Cook for 2 minutes.Mix with the pasta, stir through half the ricotta and the lemon juice, and check the seasoning.Top with the remaining dollops of ricotta. Grate over the pecorino, then cover with tin foil and bake for 20 minutes, or until golden and bubbling, removing the foil after 10 minutes.