Preheat oven to 350F. On a baking sheet with parchment paper or roasting pan, toss carrots with olive oil, fresh chopped rosemary and salt and pepper to taste.
Place in the oven and cook for about 45 minutes, turn carrots at halfway point to ensure even cooking.
While the carrots are cooking in the oven, combine the maple syrup and balsamic vinegar in a pan or small pot, and bring to a boil. Reduce the heat and simmer slowly until it has reduced by about half and is nice and thick.
Once the carrots are ready, lightly drizzle some of the syrup over them and cook them in the oven for 5 minutes more.
Serve warm or store in the refrigerator until ready to use.
Notes
You don’t have to use all of the maple balsamic reduction. Use as much as desired and store the rest in the refrigerator.
If the syrup gets hard like a caramel and is too stiff to pour, warm it in the microwave or stovetop for about one minute.