Meatballs In Mushrom Sour Cream Sauce

• 1 onion (chopped)
• 1 mushrooms
• 700 gr beef (ground)
• 240 ml sour cream
• 120 ml evaporated milk
• 110 gr sharp cheddar cheese (grated)
• 90 gr pepperidge farm bread stuffing
• 2 gr salt
• 1 gr pepper
• 1 package deviled ham