Wash butternut or Hubbard squash, remove seeds and skins and cut into 1 inch cubes. In a large saucepan, cover with salted water and bring to a boil; reduce heat and simmer until squash is fork tender, about 20 minutes. Drain in a colander and squeeze out excess moisture in a clean towel or cheesecloth.

While the squash is still hot, in a large bowl, add remaining ingredients (except parsley) and whip at medium speed until smooth. Taste and adjust seasonings, adding salt, pepper, sugar, etc., as needed.

Butter a 3 quart baking dish. Transfer whipped squash to dish and spread evenly. Cover with foil and bake in a preheated 350°F oven for 10-15 minutes before serving.

Garnish with parsley and a pat of butter, if desired.