Glad to share!
I always bake a big batch of meatballs. I use some for pasta, some for subs, some for Swedish meatballs. So yes, the meatballs are baked ahead of time, frozen and defrosted most of the way. I just add them to the hot gravy and let them simmer till fully warm again. I always use egg noodles, but you could use any pasta you like!
Gravy is simple as can be. I make a roux with about 1/4 cup flour, some cracked black pepper, and about 1/3 cup water. (If I have leftover beef drippings from cooking a roast in the freezer, I use that instead of the water -defrosted). Heat the drippings or water in a saucepan on low till warm, quickly whisk in the flour, it will look like a paste. Slowly add 3 cups beef stock (or beef broth, whichever I have on hand.) Stir any lumps out with your whisk, and cook until thickened.
If I am short on time, I've been known to use the gravy packets. But the taste of homemade is much better (at least to my hubby!)