1-2 long sweet potatoes (about a pair of inches thick), peeled
4 massive parsnips, ends cut and naked as a jaybird
5 medium beets, peeled
2 1/2 cups cream, divided (whole milk is okay, however mixture wont thicken the maximum amount or be as creamy)
4 ounces grated Parmesan, divided
1 tablespoon recent minced thyme, divided, and a lot of for garnish
1 garlic, minced
2 ounces cut Gruyere
salt and pepper to style
Preheat kitchen appliance to 400˚F.
Slice sweet potato, parsnips and beets into terribly skinny rounds (using a mandoline is easiest) and transfer every vegetable to its own bowl.
Pour 2/3 cup cream over every bowl of vegetables and high every with one/2 ounce grated Parmesan and 1 teaspoon minced thyme. Season every bowl munificently with salt and pepper and toss along till all vegetable slices ar well coated.
Pour remaining cream into all-time low of a a pair of quart (oval) baking dish and sprinkle with 1/2 ounce of Parmesan and minced garlic.
Grab a stack of sweet potatoes and line them standing au fait a bias, at the highest of the baking dish.
Follow the sweet potato with a row of parsnips, followed by a row of beets.
Repeat with the remaining sweet potatoes, parsnips and beets, making vi rows of root vegetables.
Season high of gratin with salt, pepper and sprinkle of remaining ounce of Parmesan.
Cover with foil and bake for twenty five to half-hour or till vegetables ar soft.
Remove from kitchen appliance, uncover gratin and high with cut Gruyere.
Set kitchen appliance to broil and broil gratin for three to five minutes or till bronzed and effervescent on high.
Finish with a sprinkle of recent thyme leaves. Serve.