Potato and Root Vegetable Gratin with Pecan-Breadcrumbs

Serves 6-8

Thinly sliced Yukon gold potatoes are paired with seasonal root vegetables (turnips, parsnips, rutabaga) and layered in a baking dish or cast iron skillet, then combined with a garlic-infused cream and baked until tender. Meanwhile we make a pecan-herb-breadcrumb mixture to top the gratin with a golden brown crunch.

1 1/2 lbs yukon gold potatoes
1 1/2 lbs mixed root vegetables, such as rutabaga, turnip, parsnip, celery root
2 1/2 cups heavy cream
2 cloves peeled garlic, smashed
1 sprig fresh rosemary, plus 1 teaspoon finely chopped rosemary leaves
Coarse kosher salt and freshly ground black pepper, to taste
3 tablespoons butter, plus more for the baking dish
1/2 cup panko
1/2 cup pecan pieces, very finely chopped

Preheat oven to 400˚F. Butter a 2 ½ or 3-quart baking dish and set on a baking sheet.
Peel potatoes and root vegetables. Slice evenly into ¼-inch rounds, making sure all the vegetables are about the same size to ensure even cooking.
Meanwhile, combine cream, garlic, and rosemary sprig in a small pot. Bring to a gentle simmer (be careful as it can boil over easily) then remove from heat and let steep for 10 minutes.
Arrange the potatoes and root vegetables around the prepared baking dish in neat stacks, creating a decorative fan pattern. Season generously with salt and pepper. Ladle warm cream over top (discard the rosemary sprig, but let the garlic cloves nestle among the vegetables).
Bake in preheated oven until vegetables are almost creamy-tender and most of the cream has been absorbed, about 60-80 minutes.
Meanwhile, make the topping. Melt butter in a small skillet and cook until toasty and brown. Before it burns, quickly add panko and finely chopped pecans and rosemary. Stir to combine, then remove from the heat.
Sprinkle crunchy pecan topping generously over the top of the gratin. Serve hot.