Slow cooker beef hotpot

Name: Slow cooker beef hotpot
Ingredients: 1 onion, chopped; 2 carrots, cut into 1cm/½in slices; 1 tbsp vegetable or sunflower oil; 800g/1lb 12oz beef brisket, trimmed of excess fat and cut into matchbox-size cubes, or long, thick slices; 5 garlic cloves, crushed or finely chopped; 5cm/2in piece fresh root ginger, finely grated; 1 fat red chilli, shredded (i leave the seeds in); 2 tbsp light muscovado sugar; 1 tbsp miso paste, optional, but this will add extra depth to the sauce; 6 tbsp light soy sauce; 300ml/½ pint beef stock; 1 tsp sesame oil, plus more to serve; 2 bunches spring onions, trimmed then cut into finger-length pieces; Few handfuls fresh beansprouts