Thinly slice the onion and the cabbage. Add some olive oil into a large pan and add the onions. Cook them on medium low heat until they are completely softened. Add salt and pepper, garlic powder, caraway seeds, tomato paste and sugar and mix well. Add the cabbage and cook stirring occasionally until onions and cabbage are starting to caramelize, about 30-35 minutes.While the cabbage is cooking, bring a big pot of water to a boil. Salt generously (about 2 tablespoons of salt) and cook the pasta. Reserve about a cup of pasta cooking water before you drain the pasta.Mix the pasta with the cabbage and add a bit of pasta water at a time until you are happy with the consistency, this pasta isn't saucy, but it shouldn't be too dry either. Check for seasoning and if desired serve with freshly grated Parmesan on top.