Making this classic Vietnamese noodle soup is the perfect project for a chilly weekend, writes Emma Knowles.
The tools involved are simple and few. Get hold of a large stockpot (one with at least a 12-litre capacity, larger if you plan on making double batches) and you're more or less sorted. This workhorse of the kitchen needn't be expensive, so shop around (we find Chinatown to be a treasure trove in this department and while you're there you can pick up your spices and rock sugar, too). It's worth picking up a mesh skimmer while you're at it, all the better to skim away all the bits you don't want.
The building blocks of the broth are next. Unsurprisingly, the key to success is the quality and type of bones used. We experimented with various combinations and found that bones from grass-fed animals had better flavour, and a combination of leg, marrow bone and oxtail resulted in a beautifully gelatinous broth. Order the bones from your butcher and politely ask them to cut the bones into 8cm-10cm lengths.
It's important to blanch the bones to remove any impurities before you start trying to extract all that glorious flavour. Place the bones in the stockpot, cover with cold water then bring to the boil over high heat and cook until a thick layer of grey scum rises to the surface (appetising, right?). Tip the lot into the sink, rinse the bones and pot thoroughly then return the bones to the pot and top up with cold fresh water.
You can char the onion and ginger added to the broth. This is traditionally done over an open flame and imparts a beautiful sweetness to the finished soup along with its glorious golden colour. If you don't have a gas stove or barbecue, halve the onions and slice the ginger and place them under a very hot grill. The effect won't be quite the same, but it's the next best thing. If you've used an open flame, rinse the charred onion and ginger and remove any traces of blackness which could add bitterness before adding them to the pot.
Spices are next, tied up in a muslin bundle to make it easier to remove them at the end. We've gone with cinnamon, star anise and cloves - coriander seeds, fennel seeds and cardamom are also common inclusions.
Fish sauce and rock sugar are added at this stage to form the foundations of the seasoning and then again at the end to round out the flavour of the broth. You'll find yellow rock sugar in boxes at Chinese supermarkets and it's sometimes sold as rock candy. Smash up larger chunks using a mortar and pestle before adding it to the stock.
Bring the stock to the simmer and reduce the heat to very low - enough to keep the surface just moving, but absolutely never boiling. Skim off any scum that rises to the surface and enjoy the deepening fragrance. Although some recipes call for the stock to be simmered for anywhere up to six hours, the maximum flavour is extracted from the bones by about the three-hour mark.
Although you can strain, season and eat the soup at this point (and believe us, you'll be sorely tempted by the incredible fragrance filling your kitchen by now), there will be a substantial layer of fat on the surface. The easiest way to remove this is to refrigerate the strained broth overnight so it solidifies, and then you can simply lift or spoon it off.
Whether you wait or not is up to you, but it's all plain sailing from here. Extract any precious marrow from the bones, blanch the noodles (dried are fine but use fresh if you can) and slice the brisket and fillet. Slice some chilli, quarter some limes, pick the herbs and bean sprouts and pile them onto a plate to serve at the table. All that's left is to slurp and smile your way through one of the best soups you're likely to eat. Pho real.