I have recently been doing a LOT of experimenting with French onion soup. There are so many recipe variations out there, and so many claim to be the definitive version. Of course, there’s only one real way to decide which of them is best, and that is to make them. It has taken me three years to get to the point where my recipe delivers exactly what we in my family all love.
It has been a fascinating pastime: taking ideas from here and there, making small variations in the process and ingredients; it is surprising just how much of a difference a tiny change can make in a recipe. I’m sure that a few years down the line I will be making this slightly differently but that’s the beauty of any recipe, it is just a place on a journey.
RECIPE serves 4
1kg brown onions, peeled, halved and sliced 3mm thick
1 tsp caster sugar
1 heaped tbsp plain flour
3 tbsp dry sherry
2 tbsp picked thyme leaves
1.2 litres dark vegetable stock
1 French baguette, sliced on an angle
150g Gruyere cheese, grated
Thinly slicing a large quantity of onions can be a real drag, but I use a mandolin for the job which makes it quick and easy.
In a large, heavy bottomed pan, melt the butter over a high heat then add the onions. Stir and toss thoroughly, and add the sugar. Keep your eye on the onions and stir every couple of minutes because you need to use a high heat, so you don’t want them to catch and burn. Using a lower heat significantly extends the cooking time (I have spent almost two hours caramelising onions in the past, it didn’t make any difference in the taste). The sugar aids the caramelisation process.
The onions will first turn translucent, then they will spend a long time not doing very much. Then, after maybe 20 minutes, they will start to turn golden and then caramelise; when this starts it can progress quite quickly. You will notice that the bottom and sides of your pan will blacken as the sugars are transformed, this is good because it is a storehouse of flavour… as long as it doesn’t actually burn! If it burns then your soup will be bitter, and probably inedible, so manage your heat and stirring carefully as you approach the end of the caramelisation stage.
When the onions have turned a deep, dark brown, add the flour and stir vigorously for a minute or so until the flour has been absorbed, then add the sherry to the pan along with the thyme leaves and again stir vigorously. The alcohol will burn off, and the liquid will de-glaze the bottom and sides of the pan, bringing all those sugars back into action. Add the stock, bring to the boil and simmer for ten minutes. The stock is an important, but not crucial, element. It is always best to use a good quality, preferably homemade stock, but if you resort to using bouillon powder it won’t make a massive difference – it is the onions which are the star of the show here. Test and correct the seasoning.
Meanwhile, heat a large grill to high, and toast both sides of the baguette slices. At this point you can ladle the soup into flameproof bowls, float a couple of baguette slices on top and sprinkle with the cheese before putting back under the grill so it all melts together. If you prefer, you can simply sprinkle the cheese on to the baguette slices and grill it like cheese on toast, before transferring the slices to the soup bowls.
If you prefer you can do a bit of both, everyone loves seconds after all, so it’s a good idea to have an extra plate full of toasted cheesy baguette slices on hand.