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Irresistibly Creamy Rainbow Root Vegetable Au Gratin

Root Vegetable Au Gratin
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This rainbow-hued twist on classic au gratin transforms humble root vegetables into a show-stopping side dish.

Ingredients

  • 3 Yukon gold potatoes
  • 3 sweet potatoes
  • 3 beets
  • 1 onion
  • 3 tablespoons butter
  • 3 tablespoons gluten-free flour
  • 2 cups milk
  • 1.5 cups shredded cheddar cheese
  • 1 tablespoon Dijon mustard
  • 1/2 teaspoon salt
  • 1/4 teaspoon pepper
  • 1/2 cup grated Parmesan cheese

Instructions

  1. Preheat your oven to 350°F (175°C) and lightly grease a 9-inch cast iron skillet or baking dish with butter to prevent sticking and add flavor.
  2. Prepare all vegetables by peeling and slicing them to approximately 1/8-inch thickness using a mandolin or sharp knife.
  3. Make the cheese sauce by melting butter in a medium saucepan over medium heat, then whisking in the flour to create a smooth paste. Cook this roux for about 2 minutes.
  4. Gradually pour in the milk while whisking constantly. Continue cooking and stirring until the sauce thickens enough to coat the back of a wooden spoon.
  5. Remove from heat and stir in the shredded cheddar cheese and Dijon mustard until completely melted and smooth. Season with salt and pepper to taste.
  6. Arrange your vegetable slices by placing a layer of sliced onions on the bottom, then standing the potato, sweet potato, and beet slices vertically in alternating colors.
  7. Pour the cheese sauce evenly over the arranged vegetables, making sure it seeps down between the slices.
  8. Cover the dish tightly with foil and bake for 30 minutes, then remove the foil, sprinkle with Parmesan cheese, and bake uncovered for another 25-30 minutes until the top is golden brown and bubbling.

Notes

  • Uniform slicing matters: Use a mandolin set to 1/8-inch for evenly thin slices.
  • Pre-cook dense veggies: Microwave beets for 1-2 minutes if they are particularly large.
  • Master the roux timing: Cook the flour and butter until it smells nutty.
  • Season aggressively: The cheese sauce needs to be well-seasoned.
  • Create sauce valleys: Use a knife to separate some vegetable slices after pouring the cheese sauce.
  • Rest before serving: Allow the gratin to rest for 10-15 minutes after baking.

Find it online: https://www.sweethomecook.com/root-vegetable-au-gratin/