Sweet Potato Au Gratin (Print Version)
# Ingredients:
01 -
3 pounds sweet potatoes, peeled and thinly sliced into 1/8-inch rounds
02 -
1 1/3 cups grated Parmesan cheese, divided
03 -
2 cups heavy cream
04 -
3 tablespoons fresh sage, chopped
05 -
1 tablespoon fresh rosemary, chopped
06 -
3 garlic cloves, minced
07 -
Pinch of ground nutmeg
08 -
Salt and black pepper, to taste
09 -
1 cup panko breadcrumbs
10 -
1/2 teaspoon paprika
11 -
1/4 teaspoon onion powder
12 -
1/4 teaspoon garlic powder
13 -
Pinch of cayenne
14 -
Pinch of salt
15 -
2 tablespoons olive oil
16 -
Butter, for greasing casserole dish
# Instructions:
01 -
Preheat the oven to 400°F (200°C). Peel the sweet potatoes and slice them into 1/8-inch thick rounds using a mandoline or sharp knife.
02 -
Generously grease a 9×13-inch gratin or casserole dish with butter. Sprinkle a couple of tablespoons of Parmesan cheese onto the bottom.
03 -
Arrange one-third of the sweet potato slices in the dish, overlapping slightly. Sprinkle with 1/4 teaspoon salt and a few grinds of black pepper.
04 -
In a medium saucepan, combine heavy cream, chopped sage, chopped rosemary, minced garlic, ground nutmeg, and a generous pinch of salt. Bring to a low boil over medium heat, then reduce and simmer for about 10 minutes, until reduced by 1/4.
05 -
Whisk the eggs in a medium bowl. Slowly pour the hot cream mixture into the eggs while whisking continuously to temper.
06 -
Pour one-third of the cream-egg mixture (about 2/3 cup) over the first layer of potatoes. Sprinkle 1/3 cup Parmesan cheese on top, then repeat the layering process two more times.
07 -
Cover the dish with foil and bake for 40 minutes, or until the potatoes are tender.
08 -
In a medium bowl, combine the panko breadcrumbs, remaining Parmesan cheese, paprika, onion powder, garlic powder, cayenne, olive oil, and a pinch of salt.
09 -
Remove the foil from the baking dish. Spread the prepared breadcrumb mixture evenly on top. Bake uncovered for an additional 20–25 minutes, or until the topping is browned and bubbling.
10 -
Allow the sweet potato gratin to cool slightly before serving.
# Notes:
01 -
For best results, use a mandoline for uniform potato slices.
02 -
The gratin can be prepared in advance; reheat in the oven before serving.