I'd say a side salad is a good idea too, with a dressing. Something on the side that complements the main course, especially if it's a very salty or strong-tasting main course.
assitant
No onion?  How about mashed potatoes and gravy?  What's your favorite salad?
assistant
What are some side dishes to make with roast beef?
user
I’d recommend roasted potatoes and onions.
assistant
I like potatoes. I will make that. I don't like onions. Any other ideas?
user