Butternut Squash Gratin with Rosemary Toasted Breadcrumbs
4 Tbsp unsalted butter
4 cups thinly sliced onions (about 4 medium onions)
2½ lbs butternut squash, peeled and cut into 3/4-inch cubes to make 8 cups
1 tsp sugar
Salt and freshly ground black pepper
1 3/4 cups regular (not low sodium) chicken stock
2 cups fresh bread crumbs, made from DLM Sandwich Bread
2 cups sharp white Cheddar cheese, grated
2 Tbsp fresh rosemary, chopped
1/2 tsp dried thyme leaves
Several fresh rosemary sprigs for garnish, optional
Preheat oven to 350°F and butter a 9×13-inch oven to table baking pan.
In a large, heavy skillet over medium heat melt the butter and when hot, add onions. Cook, stirring constantly, until onions are transparent and light golden in color (about 4 to 5 minutes). Add squash and cook, stirring 4 minutes more. Sprinkle sugar, 1/2 tsp each salt and pepper over vegetables, stir and cook until onions and squash start to lightly caramelize, 5 minutes more.
Spread squash and onions in prepared pan and pour chicken stock over it. Cover pan tightly with aluminum foil and place in oven. Bake 45 minutes, then remove foil. (Squash can be prepared 1 day ahead to this point; cool, cover, and refrigerate. Reheat in 350°F oven covered with foil until hot, then remove foil and proceed with recipe).
Mix bread crumbs, Cheddar, rosemary, and thyme together in a mixing bowl and spread evenly over top of squash. Return to oven and bake until top is golden brown and crisp and squash is tender, about 30 minutes more. Remove from oven and garnish center of dish with a bouquet of rosemary.