Being a child of the seventies and eighties, I’m a natural sucker for a French onion soup. The thrill of seeing molten cheese on a floating toast was (and still is) my idea of heaven, married with the umami rich depth of the ‘oniony’ broth it was unlike anything I had ever tasted before – it was Wales in the seventies after all! French Onion Soup was one of the first things my husband and I attempted for our first dinner party when we were young out of work actors living in a tiny flat in South London, oh the sophistication.
It was with memories of this that I thought I decided to try a riff on the classic. I wanted to try roasting red onions and to update the usual melting gruyere with another part of my history – Welsh rarebit. Rarebit is really just an elaborate cheese on toast with many recipe variations if you care to search the internet, but this is one that I grew up with in Cardiff and the one that we still serve at our restaurant Gastrono-me in Suffolk today.
By using red onions and red wine the soup becomes more intense in flavour and colour, and I think embodies autumn’s rich hues perfectly.

Roasted Red Onion Soup with Welsh Rarebit Toasts
Course: MainDifficulty: Medium6
servings20
minutes35
minutesIngredients
750g red onions sliced
4 tbsp of olive oil
30g butter
1 large glass of red wine
1 tsp of dark soy sauce
1tbsp of balsamic vinegar
2 tsp of sugar
2 sprigs of thyme
1 bay leaf
1-2 cloves of garlic minced
1 litre of vegetable stock
Salt and ground black pepper
½ French stick for rarebit toasts
- Welsh Rarebit Mix
200g of extra mature Cheddar cheese, grated
3 tbsp of milk
1 tsp of English mustard
1/2tsp of white pepper
Salt to taste
2 egg yolks
Directions
- Preheat the oven to 230C/450F/gas mark 8
- Put the onions in a large ovenproof crockpot, pour over the olive oil and roast for 25mins or until the onions have softened and begun to char at the ends slightly
- Remove from the oven, and transfer to a medium heat on the hob.
- Add the butter, red wine, soy sauce, balsamic vinegar, sugar, thyme and bay leaf and minced garlic
- Stir constantly until jammy and caramelised
- Pour in the vegetable stock, and season to taste, cook for a further 15 mins
- Meanwhile make the rarebit mix. Add the cheddar, mustard, salt and pepper to a bowl and beat well. Add the egg yolks one at a time, with a little of the milk and beat well after each addition. Continue until you have a golden well incorporated mix.
- When ready to serve, cut the bread into 6 rounds and toast lightly under a hot grill
- Dollop on the rarebit mix and grill until the toasts are puffy and bubbling hot
- Pour the warmed soup into bowls, and top with the melting cheesy rarebit toast