Cut squash into 1 inch chunks

Melt butter in large pot, add onion, and cook til translucent, about 8 minutes

Add squash and stock. Bring to simmer and cook til squash is tender, about 15 to 20 minutes

Remove squash chunks with slotted spoon and place in blender and puree. Return blended squash to pot. Stir and season with nutmeg, salt, and pepper