In a heavy medium saucepan, STIR together cheese, milk, mustard, Worcestershire and pepper.

COOK over low heat, STIRRING constantly, until cheese melts.

Slowly STIR half of the hot cheese sauce into beaten egg; RETURN entire mixture to the saucepan.

COOK and STIR over low heat until cheese sauce thickens slightly and just bubbles.

TOAST English muffin slices; PUT on serving plates.

PLACE slice of Canadian bacon and tomato on each muffin; TOP with hot sauce.