Cook spaghetti according to directions on package.
While noodles are cooking, saute the celery and onion in the margarine for about 5-7 minutes until just about tender.
In the meanwhile, in a bowl, dissolve bouillon in water.
Add soup, pepper, seasoning, celery/onion, and cheese; mix well.
Place spaghetti, mushrooms, and ham in bowl and pour soup mixture over top. Stir well.
Transfer to a greased 8 inch square baking dish (I use 2 pie plates, serving 1 now and freezing 1 for later).
**You can cover with foil and freeze at this time if you wish.**.
Bake uncovered at 350 degrees for 30-40 minutes (or until heated through). Feel free to just microwave this for a total of 10 minutes, stirring half way through, as long as you use microwave safe dishes!