Cheesy Sweet Potato Gratin (Printable)
Comforting sweet potato gratin layered with caramelized onions and a blend of cheeses baked golden-brown.
# What You Need:
→ Vegetables
01 - 2 lbs sweet potatoes, peeled and thinly sliced
02 - 2 large yellow onions, thinly sliced
03 - 2 cloves garlic, minced
→ Dairy & Cheese
04 - 2 cups shredded Gruyère cheese
05 - 1 cup shredded sharp cheddar cheese
06 - 1 1/2 cups heavy cream
07 - 1/2 cup whole milk
08 - 3 tbsp unsalted butter
→ Seasonings
09 - 1/2 tsp dried thyme
10 - 1/2 tsp ground black pepper
11 - 1/2 tsp salt
12 - 1/4 tsp ground nutmeg
→ Optional
13 - 1 tbsp flour for thickening
14 - 2 tbsp chopped fresh chives for garnish
# How to Make It:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Melt 2 tbsp butter in a large skillet over medium heat. Add sliced onions with a pinch of salt. Cook, stirring frequently, until deeply golden and caramelized, about 20-25 minutes. Add minced garlic during the last minute.
03 - Combine cream, milk, thyme, nutmeg, black pepper, and remaining 1 tbsp butter in a small saucepan. Heat over medium-low until steaming, without boiling. If using flour, whisk in until smooth to slightly thicken.
04 - Arrange half of the sweet potato slices in the prepared baking dish. Season lightly with salt.
05 - Spread half of the caramelized onions over the potatoes. Sprinkle with half of the Gruyère and cheddar cheeses.
06 - Repeat with remaining sweet potatoes, caramelized onions, and cheeses.
07 - Pour the warm cream mixture evenly over the layered ingredients.
08 - Cover tightly with aluminum foil. Bake for 40 minutes.
09 - Remove foil and continue baking for 20 minutes, until top is golden brown and potatoes are fork-tender.
10 - Let the gratin rest for 10 minutes before serving to set. Garnish with fresh chives if desired.
# Expert Suggestions:
01 -
- The combination of Gruyère and sharp cheddar creates this incredible depth that keeps people reaching for seconds
- Caramelized onions bring a sweetness that balances perfectly with the rich cream sauce
02 -
- Letting the gratin rest for 10 minutes before serving allows the sauce to set slightly so each slice holds its shape
- Sweet potatoes vary in sweetness, so taste the cream mixture and adjust salt accordingly before pouring
03 -
- Use a mandoline if you have one for paper-thin, even slices that cook at the same rate
- Dot the top with small pieces of butter during the last 10 minutes of baking for extra golden color