Jackson Boxer’s vegetarian recipe for brown butter pumpkin soup

The base of this easy roast pumpkin soup is rich, nutty, Halloween heaven – you can go wild with the garnishes

A lot of my early life in professional kitchens was spent making vegetable purees, which I find rather tiresome, not least because they can often lapse into baby food: creamy, bland and flattened by a cosseting blanket of dairy. With a judicious and considered approach, however, they can also be incredibly vivid, explosive and concentrated expressions of the very essence of the vegetable in question. I love this seasonal (not to mention Halloween-appropriate) soup for its simplicity of approach – essentially, you just roast a beautiful pumpkin with caramelised butter – and the remarkable complexity of its result.

When browning butter, always bear in mind that it has a high water content, and that the initial seething cook is done to evaporate this – until all the water has cooked out, you won’t get the butter high enough above 100C for the milk solids and sugars to caramelise. That’s why browning butter happens two ways, like Hemingway’s bankruptcy – gradually, then suddenly. And pay close attention, or it will burn and you’ll have to start again.

250ml vegetable bouillon (homemade, ideally; see my recipe last week) 1 delica pumpkin (800g), cut in half, deseeded and peeled (I don’t bother peeling it, but cooked pumpkin skin is an acquired taste) 250g butter 10g flaky sea salt (about 2 tsp) Sherry vinegar , to taste

To finish Creme fraiche Chilli oil Toasted pumpkin seeds Ground black pepper A squeeze of lemon

Heat the oven to 195C (175C fan)/385F/gas 5½. Pour the bouillon into a roasting tray large enough to hold both pumpkin halves, then put them cut side up in the tray.

In a frying pan, simmer the butter on a high heat until it stops foaming, then turn down the heat and cook until it’s rich, brown and nutty. Immediately pour the scalding butter evenly into the pumpkin halves, then lay a sheet of greaseproof paper over the top of the pumpkins and tightly cover the whole tray in foil. Bake for 45 minutes, until the tip of a sharp knife meets no resistance and comes out clean.

Cut the cooked pumpkin into chunks, put these and the bouillon from the tray in a food processor and blitz to a smooth puree. Add the salt and vinegar, then taste and adjust the seasoning. If the puree is too tight, add more vegetable broth just to loosen – it will depend on the water content of the pumpkin and how airtight the seal was on the foil tray.

Transfer the mix to a large saucepan and reheat gently without boiling. Check and adjust for seasoning and acidity, then ladle into bowls – I serve this soup topped with creme fraiche, chilli oil, toasted pumpkin seeds, black pepper and a squeeze of lemon; other nice garnishes might include toasted croutons, fried sage leaves, chilli and garlic butter, and salsa verde, any and all of which would be very fine additions.

Jackson Boxer is chef/owner of Brunswick House, Vesper and Dove, all in London, and culinary director of Cowley Manor near Cheltenham and the Henrietta in London