Great on crackers, this stuff tastes like real cheese and will keep for weeks in the fridge.
Heat the evaporated milk in a medium saucepan over low.
Add the grated cheese to the saucepan and stir just until melted and mixture is smooth. Add the mustard, Worcestershire sauce and cayenne. Mix thoroughly and remove from heat. Stir in the sour cream.
Pour into clean jars and cool completely before refrigerating.