1.
Preheat the oven to 180° (gas mark 6).
2.
In a large bowl, mix together the oil, lemon juice, brown sugar, salt and pepper. Peel the sweet potatoes and cut them into large wedges – or like french fries. Add them to the bowl and toss well.
3.
Cover the baking tray with baking paper, spread the sweet potatoes on it and roast for about 20 minutes, keeping an eye on them. They should remain soft.
4.
Serve as is, with a little coarse salt and fresh rosemary, if desired.