Preheat oven to 400 degrees. Line a rimmed baking sheet with parchment paper or aluminum foil for easy cleanup.
In a large bowl, toss the sweet potatoes, parsnips, rutabagas, and carrots, drizzle with olive oil.
Arrange vegetables on prepared baking sheet in a single layer. Sprinkle with garlic and rosemary or thyme, then season to taste with salt and pepper. (I like 1 teaspoon salt and 1/2 teaspoon pepper.)
Roast until vegetables are tender when pierced with a fork and browned around the edges, about 60 minutes. Stir vegetables occasionally to ensure even browning.
Sweet potatoes or yams, shallots, parsnips, rutabagas or turnips, carrots: Or any sturdy vegetables you enjoy or need to use up.
Olive oil: A good rule of thumb for any roasted vegetable recipe? Estimate 1 tablespoon of oil for every 1 pound of vegetables. Don't skimp; a coating of oil will add a subtle rich flavor and help the vegetables crisp in the oven.
Garlic: At least 3 cloves; more if you like (I often do)! Roasting tames any bite so you just taste a luscious, mildly sweet flavor.