1/4 cup (1/2 stick) unsalted butter
4 cups thinly sliced onions (about 1 pound)
2 1/2 pounds butternut squash, peeled, seeded, cut into 1/2-inch cubes
1 teaspoon sugar
1/2 teaspoon salt
1/2 teaspoon ground black pepper
3/4 cup canned low-salt chicken broth
2 cups fresh breadcrumbs made from soft white bread
2 cups (packed) grated sharp white cheddar cheese
1 1/2 tablespoons chopped fresh rosemary
1/2 teaspoon dried thyme
Preheat oven to 350°F. Butter 13x9x2-inch glass baking dish. Melt butter in heavy large skillet over medium-high heat. Add onions; sauté until onions are light golden, about 8 minutes. Add squash; sauté 4 minutes. Sprinkle sugar, salt and pepper over vegetables; sauté until onions and squash begin to caramelize, about 5 minutes.
Spread vegetable mixture in prepared dish. Pour chicken broth over. Cover tightly with foil and bake 45 minutes. (Squash mixture can be made 1 day ahead. Cool, then cover and refrigerate. Reheat in 350°F oven until heated through, about 10 minutes.)
Increase oven temperature to 400°F. Mix breadcrumbs, cheese, rosemary and thyme in medium bowl. Sprinkle over gratin. Bake uncovered until top is golden brown and crisp, about 30 minutes.
Bon Appétit November 2000
Serves 10
