Melt the butter in a heavy-based saucepan over a low heat. At the same time, in another pan, bring the ale to the boil. When the butter has melted, add the flour to the pan and stir until it forms a smooth paste.
Add the ale to the flour and butter, and mix until combined. When the ale has been combined and you have a smooth mixture again, add the cheese and return to the heat, stirring all the time, until all the cheese has melted.
Remove from the heat and leave until cool. When cool, beat the egg yolks and mustard into the mixture. Season to taste with salt and pepper.
Preheat the grill and lightly toast the bread on both sides. Spread the cheese mixture evenly between all 8 slices of toast and return to the grill until golden and bubbling.
You can top the rarebit with either poached eggs or bacon (or both if you’re feeling indulgent!). Serve with a light salad.
*Inspired Claire H. featured in the Realfood Cookbook
See more bacon recipes