Put the stock cube into a pan of water, then bring to the boil. Add the noodles, bring the stock back to the boil and cook for 2 mins. Add the broccoli and boil for 2 mins more. Reserve a cup of the stock, then drain the noodles and veg.

Heat a frying pan or wok, add the sesame oil and stir-fry the mushrooms for 2 mins until turning golden. Add the garlic, chilli flakes and most of the spring onions, cook 1 min more, then tip in the noodles and broccoli. Splash in 3 tbsp of the stock and the hoisin sauce, then toss together for 1 min using a pair of tongs or 2 wooden spoons. Serve the noodles scattered with the cashew nuts and remaining spring onions. Add a dash more sesame oil to taste, if you like.