step 1
Put the cheese, butter, Worcestershire sauce, mustard, flour and pepper into a saucepan.
step 2
Mix well and then add the beer, Guiness or milk to moisten. Do not make it too wet!!
step 3
Stir over a gentle heat until all is melted, and when it is a thickish paste, stop stirring, and swivel it around the saucepan, which it will do quite easily.
step 4
Leave to cool a little, and meanwhile toast the bread on one side only.
step 5
Spread the rarebit over the untoasted side and brown under a hot grill.
step 6
This mixture can be made and kept in the refrigerator for several days if required. Sweet white wine can be used instead of beer and gives a good flavour.
step 7
(From www.welshholidaycottages.com)