This is an amazing dish! I love the combination of bitter from the rapini and the creaminess from the ricotta. This dish is excellent with just the veggies and pasta in the ricotta cheese. But I will often add 3-4 sausages out of the casing, particularly if dinner guests are meat eaters. Otherwise this is an excellent lunch meal, vegetarian meal, or for more guests serve as an appetizer.
An alternative to sausages would be bacon, either pork or turkey, or pancetta.
It could also be served at room temp as part of a buffet since the ricotta won’t congeal and the cooked pasta won’t lose its structure and fall apart. The colder it gets the more heightened the leek and onion flavour comes forward. Substitute it with gluten free pasta, such as brown rice penne. But those types of pasta usually lose their appeal once they get cold, so serve it hot.
I’m also really partial to Molisana pasta. They use 100% Durum Wheat Semolina flour to make their pasta. It’s a higher quality of wheat and tastes really good. It’s also easier to digest and in fact when I make fresh pasta (the non-egg recipe) I use semolina flour.