Preheat oven to 400ºF.
Drizzle squash with a little EVOO and season with salt, pepper and a little freshly grated nutmeg. Roast cut-side down until tender, about 40 minutes. Let cool enough to handle, then scoop flesh out of skin and add to food processor. Puree squash with stock and honey, in 2 batches if necessary, and reserve.
Heat a drizzle of EVOO in a nonstick skillet over medium-high heat and brown the sausage, crumbling it into very small bits as it cooks, about 7-8 minutes.
While the sausage cooks, heat a pot over medium heat. Add butter and melt, whisk in flour, cook 1 minute then whisk in milk. Season with salt, pepper, a little freshly grated nutmeg and sage. Cook until thickened, about 7-8 minutes, whisking occasionally.