Arrange a single layer of rainbow carrots in the bottom of a large casserole dish, then drizzle with 1 TBSP of light olive oil and sprinkle with salt. (They usually come ready to cook, but if not, you will want to cut off the carrot tops and peel them before baking.)
Place the carrots in the oven for 15 minutes.
While the carrots are roasting, mix 1 tablespoon of melted vegan butter with 1 tablespoon of agave nectar or another sweetener. After 15 minutes of roasting, drizzle the butter and agave mixture over the carrots, mix well, then sprinkle with some thyme.
Place the carrots back in the oven for 10 additional minutes. Serve hot. Bake until tender. Garnish with parsley, thyme, or rosemary.
Notes
You need to roast the carrots at 425°F (218°C) until they are hot enough to form the glaze.
I prefer a casserole dish for roasting the carrots, as the heavy bottom prevents the glaze from burning. If you use a cookie sheet or metal baking dish, be sure to line it with parchment.
If you are using larger carrots, roast them for 20 minutes before adding the butter and agave.