You can use any assortment of firm vegetables, such as a mix of brussels sprouts, turnips, cabbages, and shallots, for this recipe.
Preheat oven to 425 degrees. Toss cabbages with thyme and oil. Season with salt and pepper.
Roast cabbages on 2 rimmed baking sheets, tossing every 15 minutes, until tender and slightly charred, about 1 hour 15 minutes.