M y Korean friend Sohye introduced me to japchae, a salty-sweet stir fry that is a national speciality. It is made with dang myun, whihc are made from sweet potato. You can find them in Asian supermarkets, where they may be called sweet potato vermicelli or cellophane noodles. If you've never tried them before they are quite different to the more widely available rice vermicelli – more chewy and elastic and definitely a useful addition to a gluten-free store cupboard. Japchae usually contains sesame oil and soy sauce, but here I've made substitutes to make it suitable for anyone who can't have those. If you're vegetarian, fry chunks of drained momen tofu in place of the beef.

Serves 4 For the sauce 5 garlic cloves 4 black olives 1 tbsp ground ginger 3 tbsp rice wine (mirin) 2 tsp sugar 3 tbsp hemp oil Salt and pepper

For the stir-fry 200g sweet potato vermicelli (dang myun) 250g stir-fry beef 2 large carrots 1 orange pepper 1 red onion 6 spring onions 4 leaves cabbage/kale 150g portobello mushrooms Hemp oil for frying

1 First make your sauce. Use a garlic press to squidge the garlic and black olives into mush and add to a bowl with the ginger, rice wine, sugar and oil. Give it all a good stir, then be generous with the black pepper and add salt to taste.

2 Place the noodles in a bowl and cover with boiling water for five minutes. Drain and rinse with cold water, then stir in 2 tbsp of the sauce and set aside. Prepare the beef by tidying it up and slicing it into thin strips. Place in a bowl with a tbsp of the sauce; stir and set aside.

3 Now prepare the vegetables: the carrots should be peeled and cut into matchsticks about the length of your index finger. Cut the pepper into matchsticks too. Peel the onion and spring onion to remove tough outer layers, then slice finely. Remove any tough stalk sfrom the cabbage and slice finely too.

4 Clean and de-stalk the mushrooms. Slice and fry in some oil in a hot wok. Once cooked, place in a large bowl to one side. Use a little more oil to fry the beef until there is no trace of pink. Add the beef to the bowl. Add more oil and fry the vegetables in batches until just cooked, then add to the bowl with the beef and mushrooms. Pour the remainder of the sauce over and stir well.

5 Finally add a little more oil to the wok and fry the noodles until hot. Spoon out the noodles on to each plate and top with the beef/vegetable mix. Serve.

What to watch out for Rice wines, including mirin, are sometimes made using wheat or hydrolysed vegetable protein (which can be made from wheat) – check the label. Also check for wheat flour in the ground ginger.

Susanna Booth is a food writer and food stylist based in London; widecirclecooking.com