In large pot over medium-high heat, add Petit Beurre EVOO. Add onion and cook until translucent. Add squash and stock. Bring to a simmer and cook until the squash is tender when pierced with the tip of a knife
Remove squash chunks with a slotted spoon and place in blender. Puree (thinning with stock from pot as needed). Return puree to pot and stir well to combine the stock and puree. Season with salt and pepper.