Sometimes pasta sauce is just too thick/rich for me with these casseroles, so I decided to use tomato soup instead and my husband and I loved it. Choose seasonings that you like, don't have to use my favourites; also sorry about the lack of amounts with the seasonings, but I just shake them in until I am satisfied. I don't generally go by the book with measurements when I cook, I just eyeball everything and adjust as necessary. I also don't add salt and pepper while cooking, because my husband and I have different preferences, so we add our salt and pepper afterwards. The pasta can be any pasta similar in size to penne, such as rotini or bow ties, whatever is preferred or on-hand. The cheese could probably be changed too, I use medium cheddar because it is my preference, but other cheeses would work nicely. I am not a fan of onions or garlic, so I don't include them in here, but I am sure most people will want to include them. I would think the best way to add those ingredients is to add them to the beef after browning or during the browning depending on preference. Serving size is based on having lots of pasta with no side dish. If you have lots of sides with this, it will make more servings. Would be good with caesar or garden salad, and garlic bread or fresh French bread. This recipe does create some dirty dishes, but I love it so much I don't care.