Place carrots, butter, sugar and ½ cup water in skillet with lid or saucepan just wide enough that the carrots can lay flat. (If carrots are too large for pan, cut them in half on diagonal.)
Bring to boil, cover, then reduce heat and simmer for 5 minutes.
Uncover and turn heat up to medium-high.
Cook, stirring often to avoid sticking, until carrots are tender and liquid has evaporated, leaving glaze on the carrots.
Add salt and pepper to taste, and toss with mint, if desired.
Serve warm, with lemon. Serves 4–6 as side dish.