If you're looking for a scrumptious seasonal side dish, try this Sweet Potato Gratin with Rosemary and Sage. The elegant presentation is second only to the incredible flavor.
Add the heavy cream, rosemary, sage, salt and pepper to a small saucepan. Warm the cream slowly over low heat.
Meanwhile, peel the potatoes and slice them into thin slices approx ⅛-inch thick. A mandolin works well for this but a sharp knife can also be used.
Layer the potatoes, alternating slices of russet and sweet potato, in a circular fashion in a shallow casserole dish.
Strain the cream mixture over the potatoes. If necessary, add more cream - enough so that the cream comes up the sides of the potatoes. (The cream shouldn't completely cover the potatoes).
Cover and bake for 35-45 minutes or until tender. (Note 1) Uncover and top with Parmesan cheese. Bake uncovered for another 5 minutes until cheese is melted and slightly brown. Garnish with fresh rosemary and sage leaves before serving.
Notes
Thicker-sliced potatoes will take longer to cook. Also, the size of the baking dish can affect baking time as well.
Cut the potatoes into thin slices. Uniformly sliced potatoes will ensure even cooking. A mandolin is a useful tool for making easy work of slicing potatoes in thin slices. If you don't have a mandolin, a sharp knife can also be used. Thinner sliced potatoes will cook faster than thicker ones.
Infuse the cream with fresh herbs. I absolutely love fresh rosemary and sage and infusing the cream with these flavors take these potatoes over the top. Don't skip this step!
To make-ahead, cook, then cool completely. Cover and refrigerate. To reheat, do so covered, in a 350-degree oven.