Beef in black bean sauce

Ingredients

• 300g/10½oz rib-eye or rump steak
• 1 tsp sesame oil
• 1 tsp sugar
• 1 pinch Chinese five-spice powder
• 1 tbsp light soy sauce
• 1 tbsp cornflour
• 1 tbsp oyster sauce
• 1 tsp dark soy sauce
• 2 tbsp rice wine
• 1 ladleful chicken stock, water, beer or lager (about 5 tablespoons)
• 2 tsp salted fermented black soy beans
• 2 garlic cloves, finely chopped
• 3cm/1¼in fresh root ginger, peeled and finely chopped
• ½ brown onion, sliced
• ½ green or red pepper, sliced
• 1 spring onion, roughly chopped, plus extra to garnish (optional)
• 3 cavolo nero or kale leaves, roughly chopped
• 2 tbsp vegetable oil
• chopped fresh coriander, to garnish (optional)