Butternut Squash Gratin with Gremolata & Golden Raisins

Preheat oven to 400 degrees F. Coat a 1 1/2-quart gratin dish or other shallow baking dish with cooking spray.

Plump raisins in hot water for 10 minutes. Drain and put in a food processor fitted with steel blade. Add parsley, lemon zest, and garlic and pulse until the mixture begins to form a rough paste, 3 to 4 times; set aside.

Heat 2 teaspoons oil in a nonstick skillet over medium-high heat. Add leeks and cook, stirring occasionally, until the leeks are limp, about 5 minutes. Season with salt and pepper and set aside.

Arrange half of the squash slices in the prepared dish. Cover with the leeks and half of the raisin mixture. Layer the remaining squash over the top. Cover tightly with foil and bake until the squash is very tender,about 1 hour.

Combine breadcrumbs with the remaining raisin mixture and sprinkle over the squash. Drizzle with the remaining 1 teaspoon oil and bake, uncovered, until the top is golden, 10 to 15 minutes longer.