This Butternut Squash, Sweet Potato, and Potato Gratin is a decadent side dish perfect for family gatherings, Thanksgiving, or holiday meals. It’s layered with creamy, cheesy goodness, and enhanced with garlic, thyme, and warm spices – the ultimate comfort food baked to golden perfection.
This might just be the most beautiful side dish I’ve ever made. If you want more side dishes to try, check out this leek and potato gratin, these roasted brussel sprouts, and these easy green beans.
Ingredient Notes
Scroll down to the recipe card for the exact quantities you need for this recipe. Below, I’ve included the ingredients used plus some notes on each for potential substitutions.
- Potatoes: Yukon Gold potatoes give a creamy texture, while russet potatoes add fluffiness.
- Cheese: Mature cheddar provides a sharp, robust flavor. Gruyère or Parmesan can be used for variation.
- Spices: Nutmeg and smoked paprika add depth. For a spicy twist, add chili flakes.
- Cream: Heavy cream creates a rich sauce, but half-and-half can be substituted for a lighter option.
Variations & Substitutions
- Vegetable Swaps: Swap butternut squash with parsnips or carrots for a different flavor profile.
- Cheese Variety: Try Gruyère, Fontina, or even a mix of cheeses for added depth.
- Dairy-Free: Use coconut cream or cashew cream and a vegan cheese alternative.
How to Make Butternut Squash, Sweet Potato, and Potato Gratin
The detailed, step-by-step instructions are in the recipe card below, but here’s an overview to guide you:
1. Preheat and Prepare Your Skillet
Preheat the oven to 375°F (190°C). Butter a 26cm cast iron skillet or casserole dish to prevent sticking.
2. Infuse the Cream
In a saucepan over medium heat, combine the heavy cream, garlic, thyme, smoked paprika, nutmeg, salt, and pepper. Heat gently until warm (avoid boiling), then remove from the heat. Stir in two-thirds of the cheese.
3. Assemble the Gratin
Arrange the sliced butternut squash, sweet potato, and potato horizontally in the skillet, overlapping slightly. This creates a visually appealing and even bake – see the photo below!
4. Add the Cream
Pour the warm cream mixture evenly over the layered vegetables, ensuring it seeps into all the layers.
5. Bake and Finish
Cover the skillet with foil and bake for 45 minutes. Remove the foil, sprinkle the reserved cheese over the top, and bake uncovered for an additional 20-25 minutes until golden brown and tender.
Let the gratin rest for 10 minutes before serving to allow the layers to set. Garnish with parsley or extra cheese if desired.
Top Tips \ Chef’s Notes
- Slice Evenly: Use a mandoline slicer for even, thin slices that cook at the same rate.
- Avoid Boiling Cream: Boiling the cream can cause it to curdle, so warm gently.
- Preparing Ahead of Time: If you want to make this dish ahead of time for Thanksgiving or Christmas, I would recommend getting up to step 4, covering the pan tightly with foil, and then storing your gratin in the fridge until you’re ready to cook it.
Storage & Reheating
- Storage: Refrigerate leftovers in an airtight container for up to 3 days.
- Reheating: Warm in a 350°F (175°C) oven or microwave until heated through.
FAQs
Can I make this gratin ahead of time?
Yes, assemble the gratin (without baking), cover, and refrigerate for up to 24 hours. Bake as directed when ready to serve.
How do I prevent the top from burning?
If the cheese starts to brown too quickly, loosely tent the dish with foil during baking.
Butternut Squash, Sweet Potato, and Potato Gratin
This rich and creamy gratin combines layers of butternut squash, sweet potatoes, and potatoes, all baked in a luscious heavy cream sauce.
Ingredients
- 1 medium butternut squash, peeled and thinly sliced (about 1/8-inch thick)
- 2 medium sweet potatoes, peeled and thinly sliced
- 2 medium Yukon Gold or russet potatoes, peeled and thinly sliced
- 1.5 cups | 375ml heavy cream
- 3 cloves garlic, minced
- 1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried thyme)
- 1/4 teaspoon ground nutmeg
- 1 tsp smoked paprika
- (optionally) 0.5tsp chili flakes
- 1 cup shredded mature cheddar cheese
- Salt and freshly ground black pepper, to taste
- 2 tablespoons butter, for greasing the baking dish
- Optional Garnish: chopped parsley
Instructions
- Preheat your oven to 375°F (190°C). Butter a 26cm cast iron skillet or similar sized casserole dish.
- In a saucepan over medium heat, combine the heavy cream, garlic, thyme, smoked paprika, nutmeg, salt, and pepper. Heat until warm (do not boil) to infuse the flavors, then remove from the heat.
- Stir in ⅔’s of the cheddar cheese.
- Arrange the sliced butternut squash, sweet potato, and potato in a pattern horizontally in the skillet (see the process photos for clarification).
- Pour over the warmed cream, ensuring it seeps into all the layers.
- Cover the skillet with foil and bake for 45 minutes. Remove the foil, sprinkle the reserved cheese over the top, and bake for an additional 20-25 minutes, or until the top is golden brown and the vegetables are tender when pierced with a knife.
- Let the gratin rest for about 10 minutes before serving. Garnish with parsley or additional cheese, if desired.
Notes
You can easily prep this recipe ahead of time - either slice the potatoes and store in an airtight container, or cover the vegetables in the cream, cover them tightly with foil, and then pop them in the oven when you're ready to cook.
Nutrition Information:
Yield: 6 Serving Size: 1Amount Per Serving: Calories: 465Total Fat: 34gSaturated Fat: 21gTrans Fat: 1gUnsaturated Fat: 10gCholesterol: 102mgSodium: 256mgCarbohydrates: 33gFiber: 5gSugar: 6gProtein: 10g