In a large saucepan, melt butter over medium heat. Cook onion and garlic for 2 min. Stir in oregano, basil, salt and hot pepper flakes and cook for 1 min. Add sausage; cook, stirring, for about 5 min or until cooked through. Add tomatoes; mash with potato masher until very broken up. Stir in tomato paste and cream. Bring to the boil; reduce heat and simmer uncovered, stirring occasionally for 15 min. Meanwhile, bring a large pot of salted water to the boil. Add pasta; cook according to package directions. Drain well; return to pot. Pour in the sauce, stirring until pasta is well coated.