Pre-heat the oven to 180°C (fan)/200°C/gas mark 6.
Beat oil, balsamic vinegar, salt and pepper together in a small jug and set aside.
Cut the end off the sprouts, remove any old looking leaves, and wash well. If large then cut in half.
Place in a roasting dish and drizzle over the oil and vinegar mix.
Roast for 20 minutes, stir and roast for another 10 minutes until soft.
