In a large skillet, add the butternut squash cubes and sprinkle with 1 tsp of kosher salt. Cover with water and bring to a simmer over high heat. Once boiling, reduce heat to medium-low and simmer until the squash is tender, about 4 to 5 minutes. Drain and set aside.

In the same skillet over medium heat, melt 2 Tbsp of unsalted butter. Add the finely chopped onion, season with 1/2 tsp salt, and cook until translucent, about 7 to 9 minutes.

Add minced garlic and chopped sage to the skillet, cooking for an additional minute until fragrant.

Add dry orzo to the skillet along with the remaining 2 Tbsp of butter, stirring occasionally until the orzo is golden brown, around 2 to 3 minutes.

Sprinkle in another 1/2 tsp of salt and pour in 2 2/3 cups of water. Bring to a simmer over medium-high heat, then reduce heat to medium-low, cover, and let it simmer until the orzo is tender and liquid absorbed, about 7 to 8 minutes.

Reserve 1 cup of cooked squash cubes. Transfer remaining squash to a blender, adding 3 tablespoons of water and blend until smooth.

Add pureed squash back to the orzo mixture, stirring until creamy. Fold in reserved squash, grated Parmesan cheese, and 1/4 tsp pepper. Cook, stirring, until cheese is melted and heated through, about 3 minutes.

Serve divided among bowls, topping with extra Parmesan and freshly cracked black pepper.