Mince the onion, place it in a saucepan and fry it with the butter until soft. Add the minced meat to the onion mixture, stir and crumble it with a wooden spoon, add the peeled tomato pulp and a pinch of salt. Cover the pan and cook over a low heat for about 40 minutes, stirring it from time to time.While cooking, to prevent the bottom of the mix to stick, add a few spoons of warm water. Towards the end, add the white wine to the sauce; at the end add the beans and the chopped parsley. Do not remove the sauce from the heat and let it cook for another few minutes.Cook the pasta in a saucepan of abundant boiling salted water; when cooked al dente, drain it and place it in the sauce’s cooking pan, and mix it accurately. Let it thicken at a warm temperature for a few minutes, serve it with a sprinkle of grated Parmesan cheese and ground pepper.