Cheesy Sweet Potato Gratin (Printable Version)
Layers of sweet potatoes, caramelized onions, and melted cheeses baked to golden brown.
# What You'll 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 (plus more to taste)
12 - 1/4 tsp ground nutmeg
→ Optional
13 - 1 tbsp gluten-free flour or all-purpose flour for thickening
14 - 2 tbsp chopped fresh chives for garnish
# How To Make It:
01 - Preheat your oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - In a large skillet over medium heat, melt 2 tbsp butter. Add sliced onions and a pinch of salt. Cook, stirring frequently, until onions are deeply golden and caramelized, about 20-25 minutes. Add garlic and cook for 1 minute more. Remove from heat.
03 - In a small saucepan, heat cream, milk, thyme, nutmeg, black pepper, and remaining 1 tbsp butter over medium-low heat until steaming (do not boil). If using flour, whisk it in until smooth to slightly thicken.
04 - Layer half of the sweet potato slices in the prepared baking dish. Season lightly with salt. Spread half of the caramelized onions over the potatoes. Sprinkle with half of the Gruyère and cheddar cheese.
05 - Repeat with remaining potatoes, onions, and cheeses.
06 - Pour the warm cream mixture evenly over the layered ingredients. Cover tightly with foil and bake for 40 minutes.
07 - Remove foil and bake uncovered for an additional 20 minutes, or until the top is golden and the potatoes are fork-tender.
08 - Let rest 10 minutes before serving to allow the layers to set. Garnish with fresh chives if desired.
# Expert Advice:
01 -
- Sweet potatoes and Gruyère are one of those combinations that make you wonder why you ever bothered with regular potato gratin
- The caramelized onions add this incredible savory depth that balances the natural sweetness
02 -
- Sweet potatoes vary in moisture content. If they seem very dry you can add a splash more cream before baking.
- The resting period is not optional. It lets the sauce set so you get clean layers when you scoop.
03 -
- Pat your sliced sweet potatoes dry with paper towels before layering to prevent excess water in the dish
- If the top is browning too fast before the potatoes are done tent it loosely with foil