If you’re looking for a cozy, comforting dish that combines the richness of sweet potatoes, the earthiness of kale, and the irresistible creaminess of Gruyère cheese, this Sweet Potato & Kale Gratin with Gruyère recipe is exactly what you need. Perfect for cold-weather dinners, holiday gatherings, or any time you want a delicious, healthy side dish, this gratin is simple to make but impresses with its layers of flavor.
Whether you’re hosting a dinner party or just treating yourself to something special, this dish will steal the show. The creamy texture, cheesy goodness, and satisfying blend of sweet potatoes and kale make it a crowd-pleaser, and with just a few key ingredients, it’s surprisingly easy to prepare.
What is Sweet Potato & Kale Gratin with Gruyère?
At its core, this gratin is a baked casserole made with thinly sliced sweet potatoes, sautéed kale, and a luscious cream sauce. The dish is topped with Gruyère cheese, known for its nutty and slightly salty flavor, which melts beautifully into the creamy mixture. To finish, a crispy breadcrumb topping adds a delightful crunch.
This Sweet Potato & Kale Gratin with Gruyère is a beautiful balance of creamy, cheesy, and savory flavors, with just a hint of sweetness from the sweet potatoes. It’s perfect as a side dish, but can also be enjoyed as a main course for vegetarians.
Origin of Sweet Potato & Kale Gratin with Gruyère
Gratins are a classic French dish, traditionally made with potatoes, cheese, and cream. The concept of layering thinly sliced potatoes with cream and cheese, then baking until golden and bubbly, has been a staple in French cuisine for centuries. The addition of kale and sweet potatoes brings a modern twist to this classic, inspired by both the rich, comforting tradition of French cooking and the trend toward healthier, plant-based ingredients.
While the combination of sweet potatoes and kale is often found in contemporary American dishes, the technique of making a gratin has its roots in French culinary traditions, particularly in regions like Savoie and Provence, where hearty dishes with cheese and potatoes are a staple.
Ingredients (Serves 6–8)
For the Gratin:
- 2 large sweet potatoes, peeled and thinly sliced (⅛–¼ inch)
- 1 bunch kale, stems removed and leaves chopped
- 1 tbsp olive oil or 1 tbsp butter
- 1 medium onion, thinly sliced
- 3 garlic cloves, minced
- 1 cup heavy cream
- ½ cup whole milk
- 1 tsp Dijon mustard
- ½ tsp dried thyme (or 1 tsp fresh)
- ½ tsp salt (plus more to taste)
- ¼ tsp black pepper
- 1 ½ cups grated Gruyère cheese (divided)
- ½ cup grated Parmesan (optional but great for flavor)
For Topping (Optional but Delicious):
- ¼ cup breadcrumbs
- 1 tbsp melted butter
- Extra thyme
Step-by-Step Directions
1. Prepare the Kale
- Heat olive oil or butter in a skillet over medium heat.
- Add onion and sauté for 3–4 minutes until softened.
- Add garlic and cook for 1 minute more.
- Stir in kale and cook until wilted, about 3–5 minutes.
- Season lightly with salt and pepper. Remove from heat.
2. Make the Cream Mixture
In a bowl or measuring cup, whisk together:
- Heavy cream + milk
- Dijon mustard
- Thyme, salt, and pepper
This creamy mixture will be poured over the layers of sweet potatoes and kale for that deliciously rich texture.
3. Assemble the Gratin
- Preheat the oven to 375°F (190°C).
- Grease a 9×13 baking dish or a deep casserole dish.
- Arrange a layer of sweet potato slices on the bottom of the dish.
- Spread a portion of the kale mixture on top.
- Sprinkle a handful of Gruyère cheese and a bit of Parmesan (if using).
- Repeat the layers (sweet potato → kale → cheese) until all ingredients are used up.
- Pour the cream mixture evenly over the entire dish.
- Top with the remaining cheese.
Optional breadcrumb topping:
Mix breadcrumbs with melted butter and sprinkle over the top for an extra layer of texture.
4. Bake
- Cover the gratin with foil and bake for 35 minutes.
- After 35 minutes, remove the foil and bake for another 20–25 minutes, or until the sweet potatoes are tender and the top is golden and bubbly.
Let the gratin rest for 10 minutes before serving.
Tips & Variations
- Caramelized onions can be added to deepen the flavor of the gratin.
- Swap Gruyère for other cheeses like Comté, Fontina, or sharp cheddar for a different taste.
- For a gluten-free version, skip the breadcrumbs or use gluten-free breadcrumbs.
- Add cooked pancetta or bacon for a smoky twist.
- Use a mandoline to get perfectly even and thin potato slices for a uniform texture.
FAQs About Sweet Potato & Kale Gratin with Gruyère
Can I make this gratin ahead of time?
Yes! You can assemble the gratin the day before, cover it, and store it in the refrigerator. When you’re ready to bake, just pop it in the oven for the final cooking time. If you refrigerate it, you may need to add an extra 5–10 minutes to the bake time.
Can I freeze Sweet Potato & Kale Gratin?
Yes, this gratin freezes well. Simply bake it first, allow it to cool completely, and then cover and freeze. When ready to serve, thaw in the refrigerator overnight and reheat in the oven at 350°F (175°C) for about 20–30 minutes.
Can I substitute other vegetables for kale?
Yes! You can use spinach, Swiss chard, or even broccoli as a substitute for kale, depending on your preference. Keep in mind that spinach will cook down more than kale, so you may need a bit more of it.
Conclusion: Sweet Potato & Kale Gratin with Gruyère
This Sweet Potato & Kale Gratin with Gruyère is the ultimate side dish for any holiday table or cozy dinner. With its perfect balance of rich cheese, creamy texture, and hearty vegetables, it’s a comfort food classic with a twist. Whether you’re cooking for family, friends, or a special occasion, this gratin will undoubtedly impress. It’s simple enough to make, yet elegant enough to serve for a festive meal. So, grab your ingredients and enjoy the comforting flavors of this delicious dish — your guests are sure to love it!
