Is it Welsh? Maybe. The Welsh certainly had a reputation for loving toasted cheese that precedes “Welsh rarebit” as a dish, so it’s possible, but we’ll likely never know if that’s where it originated. There were recipes for English rarebit and Scotch rarebit, the main difference between them and Welsh rarebit being the addition of mustard. It’s no wonder that the mustard-containing Welsh rarebit is the one that we see today, because it’s delicious.
This recipe is so simple, but so good. The combination of the crunchy toast and silky smooth cheese sauce is phenomenal, and the addition of the ale and mustard are just enough to bring out the flavor of the cheese.