Trim the sprouts and discard the outer leaves (if needed). If they’re big, cut them in half.
Put them in a saucepan, add some water and a couple of pinches of salt. Bring to the boil, then check if they’re cooked through. When a fork or skewer goes through them, drain and leave the sprouts to steam dry.
Remove the skin of the sausages, then cut/crumble the meat into small pieces.
Heat the oil in a large frying pan over medium heat. Add the onion and cook for 5 minutes. Add the sausage meat and thyme leaves, then cook for another 5 minutes. Add the sprouts, put the lid on and sauté for another 5 minutes.
Add the apple juice, chutney and chestnuts and stir until the sauce has reduced to a sticky glaze.
Keep warm until you’re ready to serve.