This is a favorite winter vegetable medley at our house.
Preheat oven to 450 degrees. If you have a convection oven - use the "Roast" setting.
Meanwhile, peel a large beet, and cut it into 1/2" to 3/4" cubes. It doesn't matter what size the cubes are - but it is important that they all be about the same size - so they cook evenly.
Toss the cubed beets with enough olive oil to coat them completely.
Sprinkle generously with freshly ground salt, pepper, dried thyme, and rosemary.
Spread the coated beets onto a shallow baking pan and roast for 15 minutes.