Peel and slice the onion, then add to a pan with 1 tablespoon of oil. Fry for 5 to 7 minutes, or until softened.Peel, finely slice and add the garlic, then peel 3 strips of zest from the lemon. Add to the pan along with the spices and bay leaf. Cook for 1 to 2 minutes.Chop the sausages and toss with the flour, then add to the pan and cook until browned all over.Pour in the tomatoes and stock, and bring to a simmer. Let it bubble away for 20 minutes, chop and add the kale and cook for 5 minutes, then serve.