Whisk the egg yolks with the crème fraîche and mustard powder. Stir in the cheese and season with sea salt and black pepper.
Now, I’m rather hoping you’ve had a go at making my Cheeky chilli-pepper chutney, but if you haven’t then you can cheat by using a good shop-bought version, or simply chop up a little fresh chilli, to your taste.
Lightly toast your slices of bread on both sides. Smear a good tablespoon of your chutney on to each slice, right to the edge, followed by a quarter of your rarebit mixture. By spreading it right to the edge, the crust won’t burn.
Grill until melted and bubbling. Divide on to plates. With a knife, criss-cross the topping and drizzle with Worcestershire sauce.