I thought my way down through the layers of this dish, considering flavors that would balance each other well. I certainly wanted to feature the richness of maple syrup, and without it being overbearing. The slight saltiness of one of my favorite cheeses, Brie with veins of bleu cheese shot through its creaminess, seemed like it might a perfect melty filling. Sweet potatoes were a natural vehicle for them all, given their bright color and natural tinge of sweetness. And even though days are bright and warm, evenings still cool rapidly - good weather for a deep gratin. —boulangere
1 large or 2 small sweet potatoes, not more than 1 pound total
4.5 ounce round of Brie au Bleu
Soft butter for brushing the casserole
1 teaspoon sea or kosher salt
Several grinds of pepper
2 ounces of your favorite maple syrup, medium amber
Peel the sweet potato(es) and slice them as thin as possible. This is an excellent job for the thin setting on a mandoline.
Trim the rind from around the edge of the round of brie, then carefully slice off both the bottom and top rinds. There is nothing objectionable about their flavor - in fact, they're very tender and you should definitely eat them with some good bread or crackers. Rather, the cheese will melt to a much better consistency within the gratin with the rind removed. Slice the Brie thinly, narrower than 1/2".
Run a pastry brush over some soft butter, then brush the inside of a 2-quart casserole, hopefully with a lid.
Arrange half of the sweet potato slices in the bottom of the casserole, fanning them apart with your fingers. Try to get the layer as level as possible. Sprinkle 1/2 teaspoon of salt over them, followed by some grinds of pepper. Drizzle 1 ounce of maple syrup over the sweet potatoes, followed by 3 ounces of heavy cream. Arrange the slices of Brie in a single layer. Over the Brie, distribute the remaining slices of sweet potato. Sprinkle with another 1/2 teaspoon of salt and some grinds of pepper. Pour over them the remaining ounce of maple syrup and the last 3 ounces of cream. Cover with a lid or aluminum foil and place in oven.
Bake for 20 minutes, then remove the lid or foil and bake for another 20 minutes. The gratin is done when the potatoes feel tender when pierced with a sharp knife, the cream is reduced and thickened, and the surface is lightly browned. Remove from oven, replace lid or foil, and let sit for 5 minutes before serving.