It is autumn down here in the shady half of the world, and on the food front this means plenty of deliciously flavoured vegetables are coming right into peak season. Fennel, celeriac, Jerusalem artichokes, parsnips and swedes (rutabaga) are all plentiful, full of flavour and blushingly cheap at the moment - but the real king of autumn are mushrooms. It is true that cultivation has meant that a few varieties of mushrooms are available in abundance all year round, but if you are looking for something tastier - something a little more exotic - wild mushrooms such as slippery jacks, saffron milk caps and morels, you wont find a better time than right now.
And what could announce the arrival of chilly weather more succinctly than a steaming bowl of homemade soup? Everyone seems to have their favourite - a good, old-fashioned chicken soup is pretty hard to beat in the popularity stakes, and a rich, red, flavour-packed tomato soup would have to be hot on its heels. However, one of my favourites would have to be a dense, hearty and dark mushroom soup.
I first made this soup many years ago, when I was still a starry-eyed trainee chef - working alongside a more jaded, yet infinitely more knowledgeable mentor. I arrived at work one chilly autumn morning to find a pile of mushrooms, some garlic and an onion or two on my prep bench. My head chef outlined the method for mushroom soup and set me to the task, and around an hour or so later I presented her with a spoon, a steaming bowl of soup and a confident smile. To her credit, she was quite consoling as she tipped my soup down the sink, and the lesson I learned as she grabbed another pot off the stove has stuck with me to this day.
You see, she had made mushroom soup as well - fully expecting my disaster-in-a-bowl. I lifted a spoon and had a taste of her soup. It was a revelation - full of earthy, mysterious and delicious flavours that lingered on the tongue long after the hot soup had been swallowed. I demanded to know how she did it. Wild mushrooms? Veal stock? Expensive wine in the base? Nope.
"I used the very same ingredients that you did" was her deflating reply.
Her simple message was thus - Fantastic ingredients are essential to a good dish, but from there technique takes over. Give 3 chefs the same ingredients and the same basic method and you will end up with three wildly different plates of food. In all likelihood one will be great, one will be okay and one will be sink-fodder.
If you want your mushroom soup to be in the great category, then read on. I watched Ronnie make her soup many, many times, perfected it, and then took it somewhere else with my own touches. Aside from the garnish, this soup has no cream. Cream of mushroom soup can be pretty tasty, but this soup is all about concentrated flavours - essence of mushroom if you will - without cream masking the pure taste. The mushrooms you use will dictate the final result of the soup. Use field mushrooms and you will end up with a dark and rich soup. Use small button mushrooms and the end product will be lighter and golden in colour - with a delicate, yet wonderful flavour. Of course, if you use a proportion of wild mushrooms, strong, gamey and earthy flavours will start to emerge. Here, I have chosen to use a large amount of big, flat field mushrooms - complemented with a few wild mushrooms for added depth, but you could make up the 1 kg of mushrooms with any you choose. Feel free to experiment here, for one of the charms of this soup is capturing the essence of each different type of mushroom, and enjoying the wide variety they provide.
Ready? Lets make soup.
Heat a large soup pot or stock pot to medium heat and melt together the oil and butter - letting them bubble. Add the onion, leek and garlic and lower the heat. Cook gently for a decent amount of time - say 15 - 20 minutes, stirring occasionally to prevent browning. Continue cooking until the onions are very soft and the whole mess smells sweet and delicious. Here is one of the big secrets of this soup - cook all the vegetables very slowly at the start to extract all their deep flavours
Add the mushrooms and stir well. Cook - still on a low/medium heat - until their juices start to run - around 5 minutes or so. Add the wine and increase the heat a little. Let the wine bubble away for a minute or two, turn the heat to low, and cover the pot with a lid. Cook, stirring occasionally, for 20 minutes. The mushrooms should have collapsed and given out plenty of yummy juices. This is where most of the mushroom flavour comes from.
Add the chicken stock and increase the temperature to medium, again covering the pot. Bring the soup to the bubble, and then turn down to a gentle simmer. Cook at this temperature, covered, for about 20 minutes.
Remove the soup from the heat and strain - keeping the liquid. Place the solids (you will need to do this in small batches) into a food processor and hit the pulse button until the mushrooms are well chopped, but still have a little texture left. Aim for chunks about twice the size of match heads. Do not process to a smooth puree under any goddamn circumstances.
Return the chopped mushroom mixture to the stock pot and add enough of the strained liquid to make a thickly textured soup. You will probably have a little liquid left over, but don't throw it away - it is richly flavoured and would be sensational in another soup or perhaps a risotto.
Bring the soup back to the simmer and add the sherry vinegar if you are using it. Add plenty of sea salt and a generous grind of black pepper. Taste the soup - does it need more salt? If it is a little flat, add a splash of white wine, which will accentuate the flavours quite keenly.
Ladle the soup out into warmed bowls and dollop with a little crème fraîche. Scatter with the sliced basil, a handful of sippets and a final grind of black pepper. Drizzle over a good lug of the best extra virgin olive oil you can afford.
This soup demands large amounts of fresh, very good quality bread - preferably sourdough, the tartness of which will compliment the earthy soup very nicely indeed. Aside from this, all that is required is a chilled glass of white wine. Viognier would be my first choice - but a marsanne, or even a lightly wooded chardonnay would play nicely as well. And if you want to get a little Ibero-adventurous, try a small glass of chilled fino sherry, which partners soup gaspingly well.