Combine the olive oil, balsamic vinegar, salt and rosemary in a small bowl and whisk together.
Chop the beets and carrots. Toss with the olive oil mixture and spread out not a sheet pan.
Roast beets and carrots for 20 minutes. I prefer to check them 10-15 minutes in and gently toss them so that more than one side gets toasty.
This recipe was based on a beet that is the size of a generous apple and large carrots. That yielded us four generous servings. Vegetables Won't Brown: A couple of reasons could cause this. Don't crowd the them. You'll notice in the photos that they are spread apart, if they are too close, they will act more like steaming rather than roasting. Too much oil or too low of an oven temperature will also stop the veggies from caramelizing. Best Oil to Use: The best oil to use when roasting vegetables is olive oil. It is the preferred oil for roasting anything over 400 degrees. Don't Cover: If you cover them, it will create steam and not roast. You won't achieve the toasty brown outside you are looking for. Air Fryer Option: Cut these up as you would for the sheet pan method and mix with the balsamic, olive oil and rosemary. Heat up the Air Fryer to 390 degrees and place the veggies in the basket or tray and cook for 12-15 minutes. Turn over half way. Make sure there is air between the vegetables. You may have to do in two batches depending on the size of your machine. Always check your Air Fryer at the earliest time when making a recipe for the first time as they all cook differently.