Cheesy Sweet Potato Gratin (Printable Version)
Layers of sweet potatoes and caramelized onions baked with melted cheese to a golden finish.
# 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 gluten-free flour for thickening
14 - 2 tbsp chopped fresh chives for garnish
# Directions:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish thoroughly.
02 - Melt 2 tbsp butter in a large skillet over medium heat. Add sliced onions and a pinch of salt. Cook, stirring frequently, until deeply golden and caramelized, about 20-25 minutes. Add garlic and cook 1 minute more.
03 - Heat cream, milk, thyme, nutmeg, black pepper, and remaining 1 tbsp butter in a small saucepan over medium-low heat until steaming. If using flour, whisk in until smooth.
04 - Arrange half the sweet potato slices in the prepared dish. Season lightly with salt. Spread half the caramelized onions over potatoes. Sprinkle with half the Gruyère and cheddar.
05 - Repeat with remaining sweet potatoes, caramelized onions, and cheese blends.
06 - Pour warm cream mixture evenly over layered ingredients.
07 - Cover tightly with foil. Bake for 40 minutes.
08 - Remove foil. Bake uncovered for 20 minutes until top is golden and potatoes are fork-tender.
09 - Let gratin rest 10 minutes before serving. Garnish with fresh chives if desired.
# Expert Advice:
01 -
- The natural sweetness of sweet potatoes meets the savory depth of caramelized onions in a way nobody expects but everyone instantly craves
- It's one of those dishes that tastes like it took hours of laborious work but mostly just needs patience while the oven does its thing
02 -
- Test your sweet potato slices with a fork before removing the foil. If they're still firm, keep it covered longer. You want them completely tender before exposing to direct heat.
- The cream mixture should be warm but not boiling when you pour it over. Cold cream can curdle and separate in the oven.
03 -
- Patience with the onions is non-negotiable. If they look done after 15 minutes, they're probably only halfway there. Push them to the edge of almost too dark.
- Sprinkle a handful of panko breadcrumbs over the top during the last 10 minutes for an irresistible crunch that contrasts perfectly with the creamy layers.