Pre-heat the oven to 350°F.
In a large roasting pan, combine the kosher salt, lemon zest, pink and black peppercorns, rosemary, and thyme and mix thoroughly. Add the carrots and beets and cover completely with the salt.
Bake until the veggies are cooked through and tender, 20–30 minutes, depending on the size of the vegetables. Once thoroughly cooked, remove from the oven and scrape off the skin using a dish towel or the back of a paring knife.