Step 1

Heat the oven to 450°F with a rack in the middle position. In a small bowl, stir together the melted butter, oil, vinegar, coriander and red pepper flakes. Brush half of this mixture on the bottom and sides of a 9-inch deep-dish pie plate. Arrange the potatoes in 2 concentric rings in the pie plate, shingling and tightly packing the slices.

Step 2

Sprinkle with salt and black pepper, then tuck the shallot slices and sage leaves between the potato slices. Drizzle with the remaining butter mixture. Cover tightly with foil and bake until a skewer inserted into the center of the potatoes meets just a little resistance, about 40 minutes.

Step 3

Uncover and bake until the potatoes are lightly browned and the edges are beginning to crisp and char, another 15 to 20 minutes. Cool on a wire rack for 10 minutes. If desired, drizzle with maple syrup just before serving.