Chop the sweet potatoes, parsnips and beets. Try to keep the size of the pieces as consistent as possible. I chopped them into pieces about 1" x 1/2".
Cut the onion into large slices and peel the garlic cloves but leave them whole.
Combine all ingredients in a 9 x 13" glass baking dish. Stir to coat the vegetables with the oil and herbs.
Roast the vegetables in the preheated oven (425 F) for 45 minutes, stirring every 15 minutes.
Notes
You can use your choice of root vegetables. Plan to use about 6 cups total of your favorite vegetables for this recipe. Parsnips, sweet potatoes and beets are my favorites, but other options would be potatoes, turnips carrots or rutabaga.If you do not have a glass baking dish, roast the vegetables on any baking sheet that is lined with parchment paper.