Place the carrots in a large frying pan in one layer. Dot over the butter and half cover with 200ml cold water. Bring to the boil, then simmer for about 8 mins until the liquid is almost all evaporated.
Sprinkle with sugar, add the sesame oil and toss the carrots in the buttery juices over a low heat for about 4 mins until glossy. Serve mixed with the sesame seeds.