- Cool and peel potatoes; slice 1/4 in. thick. Spread in greased 2-qt. casserole. In saucepan, melt butter and stir in flour until well blended. Add onion, celery, ham, broth, mayonnaise and cheese spread; cook until thickened. Season with salt and pepper, if desired. Pour ham and cheese mixture over potatoes and toss gently. Bake at 275 degrees F for 1 hour or until potatoes are tender.