Wash and cut squash in half lengthwise. Scoop out seeds.
Place cut-side down on a greased baking dish.
Bake for 35-45 minutes until fork tender.
Once cool to the touch, use a fork to scrape the strings out of the squash halves. Set squash strands and empty shells aside.
Sauce
In a large pot, melt butter over medium heat.
Add onion and cook for 2 minutes until softened but not brown.
Add garlic and cook for 1 minute.
Stir in flour and mix well. Cook for 1 minute.
Gradually whisk in milk until sauce thickens.
Remove from heat and stir in cheese until melted and mixed in.
Add pepper, salt and nutmeg. Taste and adjust as desired, especially if using mild cheese.
Mix sauce with spaghetti squash strands.
Divide mix into spaghetti squash shells or place in greased baking dish.
In separate small bowl, mix Panko crumbs, parsley and Parmesan cheese.
Sprinkle on top.
Bake in preheated oven at 375°F (190°C) for 20-30 minutes or until heated through and top is browning. If top is browning too quickly, cover with aluminum foil.
Notes
Love cheese? Old, sharp cheese provides the best flavor for this recipe. If using a mild cheese, consider adding more cheese, more seasoning or a dash of mustard powder to boost the flavor.You decide whether to bake that delicious cheesy sauce in the empty shells or in a casserole dish. Both work well, it's all about presentation.Top the sauce with a crunchy topping. Trust me, the contrast between the creamy filling and the crunchy topping is one of the best parts. In fact, the first time I made this dish my kids suggested I increase the amount of topping. I used panko crumbs and Parmesan cheese, but pretzels, crackers, bacon bits, potato chips, or toasted bread crumbs would work too.The spaghetti squash and sauce can be made 2-3 days ahead and stored in the fridge. The dish can also be assembled and stored for 2-3 days before baking. Cover with plastic wrap and store in fridge for 2-3 days, then bake as directed. Finished dish can easily be reheated and leftovers can last 3-4 days.Note: I have not tried freezing this dish and I’m not sure how well it would freeze – my biggest concern would be that the squash would turn liquidy. If you experiment with freezing – let me know how it goes.