01 -
Set oven to 375°F (190°C) and allow it to fully preheat.
02 -
Boil the sweet potato slices in a large pot of water until just tender, about 10 to 15 minutes. Drain well.
03 -
Arrange half of the cooked sweet potatoes in an even layer in a greased baking dish. Distribute half of the cranberries over the sweet potatoes.
04 -
In a bowl, whisk together the heavy cream, brown sugar, cinnamon, salt, and pepper until fully combined.
05 -
Pour half of the cream mixture over the first layer. Layer the remaining sweet potatoes and cranberries, then pour the rest of the cream mixture evenly on top.
06 -
Sprinkle the shredded Gruyère cheese evenly over the assembled gratin, then top with breadcrumbs.
07 -
Bake on the center rack for 30 to 35 minutes until the top becomes golden brown and the filling is bubbling.