1tbspolive oilor a little more, as needed during cooking
½clovegarlic(or 1 small) finely chopped
Mix together the oil, maple syrup, cinnamon, garlic and chili (if using). Preheat oven to 400F/200C.
Wash the sweet potatoes well, dry them then trim one side to make slightly flat, if needed (I didn't need to with the longer thinner sweet potatoes that I had).
Put a sweet potato on a chopping board with wooden chopsticks either side of it. Make cuts all along at regular intervals, around ¼in/1/2cm apart. Repeat with the other sweet potatoes.
Put the sweet potatoes in a roasting dish or skillet and drizzle over the oil mixture. Use a brush to get the oil mixture into the cuts and spread all over.
Roast for around an hour, or longer if they are thicker, until the inside is tender. You may want to baste now and then with any oil mixture at the bottom of the pan and/or a little extra oil and maple if they appear a bit dry.
Note: I had three sweet potatoes each around 5oz/150g - larger sweet potatoes will need to cook a bit longer.