Baked Leek and Sweet Potato Gratin

Loved this one revised from Vegetarian Times. It was a great alternative to the usual sugar- and fat-filled holiday fare.

3 leeks, sliced (green and white parts) and rinsed well
1 1/2 tablespoons olive oil divided
3 cloves garlic, minced
3 Tablespoons very finely chopped fresh rosemary
3 large sweet potatoes, peeled and sliced into 1/8-inch slices (the v-shaped blade of the Pampered Chef Ultimate Mandolin was perfect)
1/2 cup vegetable broth
1/2 cup panko bread crumbs

Preheat oven to 450-degrees.

Heat 1 T. oil in non-stick skillet over medium-high heat. Add leeks, garlic and rosemary; saute 8 minutes, or until softened. Season with salt and pepper, if desired. Arrange one-third sweet potato slices on the bottom of a stoneware square baker or oiled casserole dish, overlapping slightly. Spread half of leek mixture on top. Arrange another one-third sweet potatoes over leeks; top with remaining leeks, followed by remaining sweet potatoes. Drizzle broth over top, cover with foil and bake 35 minutes.

Stir together breadcrumbs and remaining oil. Remove foil from gratin, and sprinkle with bread crumb mixture. Bake uncovered 15 minutes, or until breadcrumbs are lightly browned and crisp. Cool slightly before serving.