|Shredded sharp cheddar cheese||2 Cup (32 tbs)|
|Shredded american cheese||1 Cup (16 tbs)|
|Milk||3⁄4 Cup (12 tbs)|
|Dry mustard||1 Teaspoon|
|Egg||1 , slightly beaten|
Combine cheese, milk and mustard in top of double boiler.
Heat over hot water, stirring constantly until cheese is melted and mixture is blended.
Beat in egg and margarine.
Cook, stirring, 5 minutes longer.
Transfer to fondue pot or warmed bowl.