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Butternut Squash Casserole

A warm, savory-sweet casserole featuring roasted butternut squash and Honeycrisp apples, browned Italian sausage, caramelized fennel and onion, maple syrup, fragrant herbs, and a golden layer of melted Gruyère. Fresh or crisp-fried sage provides the finishing touch.
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Course: Casserole
Cuisine: American
Keyword: Butternut Squash Casserole
Cook Time: 35 minutes
Total Time: 35 minutes

Ingredients

For the Squash and Apple Mixture

  • 1 tablespoon pure maple syrup
  • ½ teaspoon dried ground sage
  • 2 pounds butternut squash peeled and chopped into 1-inch cubes
  • Black pepper according to taste
  • 1½ teaspoons herbes de Provence
  • 2 tablespoons extra-virgin olive oil
  • 2 Honeycrisp apples peeled, cored, and cut into pieces approximately the same size as the squash
  • Salt to taste

For the Sausage and Caramelized Vegetables

  • 2 small fennel bulbs halved, cored, and finely sliced
  • Olive oil as required for cooking
  • ½ pound sweet Italian sausage removed from the casings and crumbled
  • 1 onion quartered and sliced into thin strips

For Assembly and Garnishing

  • Fresh sage leaves for serving
  • 1 cup shredded Gruyère cheese
  • Salt and freshly ground black pepper as needed
  • 1 tablespoon maple syrup
  • ¼ cup oil for frying the sage leaves, optional

Instructions

  • Preheat the oven to 425°F. Cover a baking sheet with foil and lightly coat it with cooking spray.
  • Place the cubed butternut squash and prepared Honeycrisp apples in a large mixing bowl.
  • Pour approximately 2 tablespoons of olive oil over the squash and apples. Season generously with salt and black pepper.
  • Add 1 tablespoon of maple syrup, the dried sage, and herbes de Provence.
  • Toss thoroughly until the squash and apple pieces are evenly coated with the oil, syrup, herbs, and seasonings.
  • Arrange the mixture across the prepared baking sheet in an even layer. Roast for approximately 35 minutes, stirring occasionally to encourage even browning. Continue roasting until the butternut squash is tender.
  • While the squash and apples are roasting, place a large skillet over medium-high heat. A cast-iron skillet may be used.
  • Add a small amount of olive oil to the heated pan.
  • Once the skillet is hot, add the crumbled sweet Italian sausage.
  • Cook for several minutes, stirring periodically, until the sausage is thoroughly cooked and nicely browned.
  • Transfer the cooked sausage to a bowl and reserve it for assembly.
  • Place the thinly sliced fennel and onion in the pan. Cook over medium heat for approximately 10 to 12 minutes, stirring from time to time.
  • Continue cooking until the vegetables develop a deep golden color and a soft, jam-like consistency.
  • Transfer the caramelized fennel and onion to the bowl containing the cooked sausage.
  • Add a little additional olive oil to the skillet if the surface appears dry.
  • For additional sweetness and deeper caramelization, the vegetables may remain over low heat for an extra minute before being removed from the skillet.
  • Change the oven setting from roasting to broil.
  • Combine the roasted squash and apples with the cooked sausage, fennel, and onion in a large bowl.
  • Drizzle the remaining 1 tablespoon of maple syrup over the mixture and toss until the ingredients are evenly distributed.
  • Taste and season with additional salt and black pepper as desired.
  • Transfer the combined mixture to a medium baking dish measuring approximately 9 × 13 inches.
  • For a crisp sage garnish, heat ¼ cup oil in a small saucepan over medium-high heat.
  • When the oil begins to shimmer, carefully add the fresh sage leaves.
  • Fry the leaves for approximately 20 seconds, or until crisp.
  • Immediately transfer them to a paper towel-lined surface to drain. Season lightly with salt and reserve for garnishing.
  • Scatter the shredded Gruyère evenly over the assembled casserole.
  • Place the baking dish beneath the broiler for a few minutes, watching carefully, until the cheese has melted and developed a golden-brown surface.
  • Remove the casserole promptly once the cheese is browned, as broilers can color the topping very quickly.
  • Allow the casserole to cool slightly after removing it from the oven.
  • Finish with either the fried sage leaves or fresh sage leaves.
  • Serve the casserole warm.
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Notes

Gruyère contributes a distinctive nutty flavor to the casserole. A combination of Gruyère and Swiss cheese may also be used.
The sage garnish may be served fresh or fried, depending on the preferred texture.