I can't get enough squash in the winter, and when we have some leftover (like from the risotto below), I like to make an easy puree as a side dish.
3 C butternut squash, peeled and chopped into 1" pieces
2 Tbs butter
4 Tbs mascarpone cheese (or heavy cream)
2 Tbs brown sugar
Pinch of nutmeg
1 tsp cinnamon
Boil the squash until tender. Drain and return to pot. Allow any extra water to evaporate, and then use a potato masher to mash. Stir in the remaining ingredients.