To add some complex flavours to your sauce, you can use tomato sauce with seasoning added to it such as the sweet basil sauce I recommend. This sauce is the Classico brand, but feel free to use whatever sort of pasta sauce is your favourite! If you don't want to use jarred pasta sauce, you can make your own tomato sauce by mixing together strained/crushed tomatoes, some Italian seasoning, salt & pepper, a tiny bit of brown sugar and a little garlic.