Preheat oven to 400°
Steam squash, covered, 9 minutes or until tender.
Heat oil in a large nonstick skillet over medium heat. Add leek; sauté 5 minutes or until lightly browned.
Combine squash, leek, apple, sugar, salt, nutmeg, and pepper in a large bowl; toss gently to coat. Spoon into a 2-quart casserole coated with cooking spray, and pour cider over squash mixture. Cover and bake at 400° for 20 minutes.
Place bread in a food processor; pulse 10 times or until coarse crumbs form to measure 1 cup. Combine breadcrumbs, pine nuts, and butter. Uncover the casserole; sprinkle with breadcrumb mixture. Bake, uncovered, an additional 15 minutes or until golden brown.