A bit of a riff on the breakfast-for-dinner idea: a puffy, slightly spicy, cheese soufflé spooned over sliced French bread and baked; served with maple roasted bacon and a spinach salad with almonds, apples, pears, and lemon poppy seed dressing on the side.
I saw Jennifer Paterson (of the Two Fat Ladies fame) make this bit o’ cheddar and eggs a while back, and HAD to go digging in the book stacks downstairs – I knew we had all of their cookbooks.
SUCCESS! The only bad part of this recipe is that most of it is done at the last minute – giving your kitchen this look. But it really wasn’t THAT bad – I had made the French bread earlier in the week, and probably could’ve gotten by using just the one mixer, but I have two, so thought I may as well use them and save on washing out bowls mid-recipe.
INGREDIENTS
•8 oz sharp cheddar cheese, grated
•4 eggs, separated
•1 tsp dry mustard, I use Colman’s
•Worcestershire sauce
•Hot pepper sauce
•Salt and freshly ground black pepper
•2 large slices good white bread – I used four thin slices of homemade bread, and think it worked fine, tho’ can see where piling the soufflé all on top of just two slices would make for a richer serving
•Butter – for the baking dish
Put the cheese in a bowl and beat in 3 egg yolks (the fourth is extra, use it for something else, or, if like me you have no other use at hand for a lone yolk, chuck it down the disposal – wasteful, mebbe, but preferable to stashing the yolk in the fridge with all good intentions, only to come across it at some far later date, resulting in the chucking of the yolk AND the container, ‘cause you’re afraid of opening the thing up), a level teaspoon of mustard, a good shake of 
the Worcestershire and hot pepper sauces, and season to taste.
I went back a couple of times, adding more Worcestershire, Tabasco, salt and pepper – remember that Welsh Rarebit SHOULD have a bit of a bite, and remember, too, that when you’ve folded in the whipped egg whites, all that flavor will be dispersed among a much larger volume.
Toast the bread and preheat the oven to 450º.
Whip the 4 egg whites until they stand in stiff peaks (I used the stand mixer with the whisk attachment for this). Add a spoonful 
or so to the cheese mixture then gently fold the rest of them into the bowl.
Put the toasts into a well-buttered ovenproof dish and pour the mixture over them. The original recipe didn’t call for the buttered dish part, but I think it would soften the toast a bit while baking, as well as adding an extra hit of goodness.
Bake for 10 minutes until nicely browned and risen.
Serve at once, and enjoy.
NOTE: After sleeping on this, I’m thinking that you might could do a fair bit of this recipe ahead of time – separating the eggs, beating the yolks with the cheese and seasonings – and only do the last bit of whipping the whites, folding it all together, and then baking just before serving. I may have to try this on our next group of brunch guests.