Steps

1. Preheat the oven to 400 degrees.
2. Cut the squash in half lengthwise. Scoop out the seeds, season the flesh with salt and pepper, and fill the cavities with the peeled garlic cloves and the sage leaves. Place the squash, skin side down, in a large baking dish with enough water to barely cover the bottom (this will prevent burning).
3. Bake for about 45 minutes or until completely tender. Cool and discard the garlic and sage.
4. Melt the butter in the milk. Scoop the squash flesh out of the skins and pass through a food mill, then whisk the milk and butter into the squash. Adjust seasonings and serve warm.