Preheat your oven to 400°F (200°C). Slice the delicata squash lengthwise and scoop out the seeds.

Toss the squash with sliced sweet onion, olive oil, sea salt, and black pepper. Spread on a sheet pan and roast for 30 minutes, flipping halfway through.

Bring a pot of salted water to a boil. Cook the pasta as per package directions until al dente, then drain.

Melt butter in a pot over low heat. Add minced garlic and chopped sage, cooking for 5-6 minutes until fragrant.

Stir in flour to form a roux, then whisk in milk gradually until the sauce thickens.

Fold in the roasted squash and onions, followed by the cooked pasta. Heat through for 1-2 minutes before serving.