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cheesy root vegetable gratin
Sarah

Ultimate Cheesy Root Vegetable Gratin

This Cheesy Root Vegetable Gratin brings warmth and joy to any meal. It’s a stunning side dish that feels fancy but is surprisingly simple to make, blending earthy root vegetables with a rich, creamy sauce and golden cheese.
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Prep Time 15 minutes
Cook Time 50 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: one-pot meal, Side Dish
Cuisine: French
Calories: 265
Ingredients Equipment Method Notes

Ingredients
  

  • 1 tablespoon unsalted butter softened
  • 1-2 long sweet potatoes about 2 inches thick, peeled
  • 3-4 large parsnips ends trimmed and peeled
  • 3-5 small beets peeled
  • 14 tablespoons heavy cream divided (whole milk is fine, but mixture won't thicken as much or be as creamy)
  • 4 ounces grated Parmesan divided
  • 1 tablespoon fresh minced thyme divided (plus more for garnish)
  • 1 clove garlic minced
  • 1 ounce shredded gruyere
  • salt and pepper to taste

Equipment

  • mandoline slicer
  • 3-quart baking dish
  • Mixing Bowls
  • measuring spoons and cups
  • Sharp Knife
  • vegetable peeler

Method
 

  1. Preheat your oven to 400˚F. Generously grease a 3-quart baking dish with softened unsalted butter.
  2. Carefully slice the peeled sweet potatoes, parsnips, and beets into very thin rounds. A mandoline slicer makes this easiest and ensures uniform thickness. Transfer each type of sliced vegetable to its own separate bowl.
  3. Pour 4 tablespoons of heavy cream over both the sweet potato slices and the parsnip slices. Pour the remaining 2 tablespoons of cream over the beet slices.
  4. To each bowl of sliced vegetables, add ½ ounce of grated Parmesan and 1 teaspoon of minced fresh thyme. Season each bowl generously with salt and pepper. Toss each bowl thoroughly until all vegetable slices are well coated with the creamy mixture and seasonings.
  5. Pour the remaining ¼ cup of heavy cream into the bottom of the prepared 3-quart baking dish. Sprinkle it with ½ ounce of Parmesan cheese and the minced garlic.
  6. Begin arranging your gratin: Grab a stack of sweet potato slices and line them standing up, slightly on a bias, at one end of the baking dish. Follow this with a neat row of parsnip slices, then a row of beet slices.
  7. Continue this pattern, repeating with the remaining sweet potatoes, parsnips, and beets, to create approximately six beautiful rows of root vegetables.
  8. Season the top of the assembled Cheesy Root Vegetable Gratin with a final sprinkle of salt and pepper, and the remaining Parmesan cheese.
  9. Cover the baking dish tightly with aluminum foil and bake for 30 minutes, or until the vegetables have softened.
  10. Carefully remove the foil from the gratin. Evenly sprinkle the shredded Gruyère cheese over the top.
  11. Return the uncovered gratin to the oven and continue baking for an additional 18 to 20 minutes. Bake until the vegetables are fork-tender, the cheese has melted beautifully, and the top has lightly browned to a perfect golden crisp.
  12. Finish your delightful gratin with a sprinkle of fresh thyme leaves for garnish. Serve immediately and enjoy!

Notes

For best results, slice vegetables uniformly thin, ideally with a mandoline. To prevent beets from coloring the entire dish, you can blanch them lightly first. Ensure vegetables are dry before mixing to avoid a watery gratin. If vegetables are still hard after the initial baking, cover and bake longer. This gratin can be prepared up to 24 hours in advance, stored in the refrigerator for 3-4 days, or frozen for 2-3 months (both baked and unbaked). Reheat gently in the oven or microwave.