Cook pasta shells according to package directions. Meanwhile in a large saucepan, cook sausage over medium heat until no longer pink; drain. Set half of the sausage aside for filling.
Add the tomato sauce, tomato paste, water, brown sugar & Italian seasoning to the remaining sausage. Bring to a boil. Reduce heat; simmer, uncovered for 15 min. stirring occasionally.
Drain pasta. In a large bowl, combine the cottage cheese, 1 c mozzarella, egg, parsley and reserved sausage. Stuff into shells.
Spread ½ c meat sauce into an ungreased shallow 2 qt. baking dish. Arrange stuffed shells in a dish; drizzle with remaining meat sauce. Sprinkle it with remaining mozzarella & parmesan.
Baked, uncovered at 350º for 25-30 min.