1 cup light brown sugar
6 tablespoons unsalted butter, cut into 1 tablespoon pieces
1 teaspoon salt
1 1/2 lb sweet potato, peeled, sliced into 1/8-inch rounds
1/4 cup neutral oil (canola, vegetable, grapeseed)
1 teaspoon ground nutmeg
1 teaspoon ground dried ginger
1 teaspoon ground cinnamon
1 teaspoon ground coriander
1 unrolled pie crust
1 egg, beaten
DirectionsPreheat oven to 375°F. Place sugar and 1/4 cup water in large cast iron skillet and bring to boil. Continue to cook until caramel has reached 350°F. Whisk in butter one piece at a time, fully incorporating before adding the next. Add salt.
Combine in mixing bowl: sweet potato rounds, oil, nutmeg, ginger, cinnamon and coriander until well blended. Arrange sweet potatoes in a spiral starting at the center of the pan and working outwards, repeating in layers until all sweet potatoes are used. Bake 15–20 minutes until sweet potatoes are fork tender.
Roll out crust until it is slightly larger than the diameter of the pan and place over cooked sweet potatoes, tucking edges inside the pan. Cut 6 slits in top of crust for venting and brush the entire crust with egg. Return to oven and bake 15–20 more minutes until crust is golden brown. Let rest at room temperature 30 minutes, run a paring knife around the edge to release crust, and invert onto cutting board.