In a small bowl, whisk all ingredients for the dipping sauce together until combined. Cover and refrigerate until ready to use.
To Prepare the Root Chips:
Preheat the oven to 400ºF.
Whisk together the oil, dried thyme, garlic powder, ground cumin and salt in a small bowl.
Peel all of the root vegetables and use a mandoline slicer to slice them ⅛-inch thick. (You can also slice them thinly using a sharp knife, but be very careful, as roots tend to be difficult to cut.)
Use a brush to lightly coat both sides of each chip with oil, then place the slices on an oven-safe wire rack, making sure the slices do not overlap. Place the wire racks on 2 baking sheets. (If you don't have enough wire racks or baking sheets, you can make the chips in 2 batches.)
Place the baking sheets in the oven and bake the roots until golden-brown and crispy. Check on the roots every few minutes once they have been baking for 20 minutes; remove any chips that are brown and crisp and return the rest to the oven until they're all done baking.
Serve fresh out of the oven with buttermilk-parsley dipping sauce.
Craving more veg-friendly recipes? Shop our collection of vegetarian and vegan cookbooks, including our new Vegan Thanksgiving and Vegan Christmas cookbooks!