Description
Sweet Potato & Beet Gratin is a comforting layered side dish made with tender sweet potatoes, earthy beets, creamy Yukon Gold potatoes, sautéed onions, and a rich Parmesan cream sauce, finished with golden Gruyère, crispy fried onions, fresh thyme, and pomegranate seeds.
Ingredients
2 large sweet potatoes (about 700 g), peeled and thinly sliced
3 medium beets (about 450 g), peeled and thinly sliced
2 large Yukon Gold potatoes (about 400 g), peeled and thinly sliced
1 small yellow onion, thinly sliced
2 tbsp olive oil
2 garlic cloves, minced
1 tsp fresh thyme leaves
1/2 tsp dried rosemary
1/2 tsp salt
1/4 tsp black pepper
1 cup (240 ml) heavy cream
1/2 cup (120 ml) vegetable or chicken broth
1/2 cup (50 g) grated Parmesan cheese
1/2 tsp garlic powder
1/4 tsp nutmeg
1/2 tsp salt
1/4 tsp black pepper
1/2 cup (50 g) shredded Gruyère or mozzarella cheese
2 tbsp grated Parmesan cheese
2 tbsp crispy fried onions or shallots
1 tbsp fresh thyme leaves
1/4 cup (40 g) pomegranate seeds
Instructions
1. Preheat your oven to 375°F (190°C). Lightly grease a 9 × 13-inch (23 × 33 cm) baking dish with olive oil and set it aside.
2. Peel the sweet potatoes, beets, and Yukon Gold potatoes. Using a sharp knife or mandoline, slice all the vegetables very thinly and as evenly as possible.
3. In a medium bowl, whisk together the heavy cream, vegetable or chicken broth, Parmesan cheese, garlic powder, nutmeg, salt, and black pepper until smooth and well combined.
4. Heat 1 tbsp olive oil in a skillet over medium heat. Add the sliced onion and cook for 4–5 minutes, stirring occasionally, until softened and lightly golden. Add the minced garlic and fresh thyme and cook for another 30 seconds, just until fragrant. Remove from the heat.
5. Arrange the sweet potato, beet, and Yukon Gold potato slices in alternating rows inside the prepared baking dish. Tuck some of the softened onions between the slices, spreading them as evenly as possible.
6. Slowly pour the creamy Parmesan sauce evenly over the vegetables. Gently press the slices down if needed so the sauce can reach between the layers.
7. Cover the baking dish tightly with aluminum foil. Bake for 45 minutes, allowing the vegetables to steam gently in the creamy sauce and become tender.
8. Carefully remove the foil. Sprinkle the shredded Gruyère or mozzarella evenly over the top, followed by the remaining grated Parmesan cheese.
9. Return the uncovered gratin to the oven and bake for another 25–30 minutes, until the vegetables are completely tender and the cheese is melted, bubbling, and golden brown.
10. During the final 5 minutes of baking, sprinkle the crispy fried onions or shallots over the top so they become golden and crunchy without burning.
11. Remove the gratin from the oven and let it rest for 10–15 minutes. This allows the creamy sauce to settle and helps the layers hold together when serving.
12. Finish with fresh thyme leaves and scattered pomegranate seeds. Serve warm as a festive holiday side dish, vegetarian centerpiece, or comforting addition to a family dinner.
Notes
Slice the vegetables evenly and as thinly as possible so the sweet potatoes, beets, and Yukon Gold potatoes cook at the same rate.
A mandoline makes slicing easier and more consistent, but use the safety guard and protect your fingers.
Cover the gratin during the first stage of baking. The foil helps the vegetables become tender without allowing the top to dry out.
Let the gratin rest for 10–15 minutes after baking. This allows the creamy sauce to thicken slightly and makes serving easier.
Add crispy fried onions or shallots near the end of baking so they stay crunchy and don’t become too dark.
Fresh pomegranate seeds provide a bright, juicy contrast to the rich cream, cheese, and roasted vegetables.
You can assemble the gratin several hours ahead, cover it tightly, and refrigerate it until ready to bake. A chilled gratin may need additional oven time.
Russet or another potato variety can be substituted for Yukon Gold, although Yukon Gold potatoes provide a naturally creamy texture and buttery flavour.
Goat cheese can be used instead of Gruyère. For a balanced topping, combine a smaller amount of goat cheese with Parmesan.
The gratin is ready when a thin knife slides easily through the thickest vegetable slices and the cheese is melted, bubbling, and golden.
For a vegetarian version, use vegetable broth instead of chicken broth.
Serve with roasted turkey, chicken, pork, or beef. For a meat-free meal, pair it with a green salad, roasted Brussels sprouts, sautéed greens, or crusty artisan bread.
- Prep Time: 25 minutes
- Cook Time: 1 hour 15 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: American