(from Great British Cooking by Jane Garmey)

2 1/2 cups grated good cheddar cheese
1 ounce butter
1/2 cup strong ale
2 tsp Colman dry mustard
Salt and pepper
buttered toast points

Melt the cheese and butter in the ale in a small pan. Stir over low heat until the cheese is completely melted. Stir in the mustard salt and pepper. Arrange the toast points in an oven proof dish, pour the cheese mixture over the toast and broil until the cheese is bubbling and brown. For a not very traditional version use steamed cauliflower in place of the toast.

This is also sometimes called Welsh Rabbit.