Go Back

Rustic Root Vegetable & Kale Gratin

A creamy, cheesy baked casserole with layers of seasonal root vegetables and kale for the ultimate winter comfort food.
Print Recipe Pin Recipe
Prep Time 30 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 45 minutes
Servings: 8 servings
Course: Main Course, Side Dish
Cuisine: American, French
Calories: 380

Ingredients
  

Vegetable Layers
  • 1 large Yukon Gold potato peeled, thinly sliced (1/8")
  • 1 medium sweet potato peeled, thinly sliced
  • 1 large parsnip peeled, thinly sliced
  • 1 small celery root (celeriac) peeled, thinly sliced
  • 1 bunch Lacinato kale stems chopped, leaves torn
  • 2 large shallots thinly sliced
  • 3 cloves garlic minced
  • 2 tbsp extra-virgin olive oil
  • 1 tsp fresh thyme leaves plus sprigs for garnish
  • 1 tsp fine sea salt divided
  • Freshly ground black pepper
Cream Sauce
  • 1.5 cups heavy cream or full-fat coconut milk
  • 0.75 cup vegetable broth
  • 2 tsp Dijon mustard
  • 1 tsp fine sea salt
  • 0.5 tsp freshly grated nutmeg
  • 0.25 tsp cayenne pepper optional
Cheese Topping
  • 1 cup grated Gruyère cheese about 4 oz
  • 0.5 cup grated Parmesan cheese about 2 oz
  • 0.33 cup panko breadcrumbs optional

Equipment

  • 9x13-inch baking dish
  • Mandoline slicer (recommended)
  • Large Mixing Bowls
  • Cheese Grater

Method
 

  1. Preheat oven to 375°F (190°C). Grease a 9x13 inch or 3-quart baking dish.
  2. In a large bowl, combine sliced potatoes, sweet potato, parsnip, celery root, kale STEMS, shallots, garlic, olive oil, thyme, ½ tsp salt, and pepper. Toss to coat.
  3. In a separate bowl, toss the torn KALE LEAVES with a pinch of salt. Massage with hands for 30-60 seconds until softened and dark green.
  4. Whisk cream, broth, Dijon, 1 tsp salt, nutmeg, and cayenne in a jug or bowl.
  5. Spread half the root veg mix in the dish. Top with half the kale. Pour half the cream sauce over.
  6. Repeat layers with remaining vegetables, kale, and cream sauce.
  7. Cover tightly with foil. Bake for 45 minutes.
  8. Remove foil. Mix Gruyère and Parmesan; sprinkle evenly over top. Add panko if using. Bake uncovered for 25-30 mins until golden and bubbly.
  9. Let rest for 15-20 minutes before serving. Garnish with thyme.

Notes

Resting is essential for the gratin to set. Leftovers reheat beautifully in the oven or microwave. For a dairy-free version, use full-fat coconut milk and a vegan cheese alternative.