Caramelized onions and crispy bacon make this butternut squash casserole recipe stand out from the casserole dish competition. Serve this butternut squash-bacon casserole as a holiday or Sunday dinner side.
In a large Dutch oven cook butternut squash, covered, in enough boiling salted water to cover for 25 to 30 minutes or until tender; drain. Return to pan.
Preheat oven to 350 degrees F. Grease a 3-quart rectangular baking dish; set aside. Mash squash with a potato masher. Gradually stir about 1 cup of the mashed hot squash into the beaten eggs. Return mixture to remaining squash in pan. Add butter, brown sugar, the 1/4 cup maple syrup, and the milk. Whisk until well combined. Transfer squash mixture to the prepared baking dish.
Bake, uncovered, for 25 minutes. Meanwhile, cook bacon and onion over medium heat about 10 minutes or until bacon is slightly crispy and onion is tender, stirring frequently. Remove from heat, drain off any excess fat. Stir in cinnamon.
Top casserole with the bacon and onion mixture. Bake, uncovered, about 10 minutes more or until edges are set and casserole is heated through. Drizzle with additional maple syrup. Let stand for 10 minutes before serving.