Preheat the oven to 425 degrees.
Line a large, rimmed baking sheet with aluminum foil for easy clean-up; set aside.
If your carrots are larger than 3/4" in diameter in the thickest part, cut them down so they will all bake about the same time.
In a gallon zip-top bag, place the brown sugar, maple syrup, salt, pepper, garlic powder, cumin, and melted butter. "Massage" the bag to combine the ingredients.
Add the carrots to the bag and seal the top very well. Using your hands, massage the bag to cover the carrots with the brown sugar mixture.
Pour the carrots onto the lined baking sheet, placing them in one layer.
Bake for 20 minutes. Remove from the oven and toss the carrots to coat.
Bake for another 20 minutes and check for caramelization. Continue to bake for another 10 minutes or so, or until the brown sugar mixture has thickened and the carrots are nicely glazed.
Remove from the oven. Sprinkle with cilantro if desired and serve warm.