steaming produce more water, which if you use in baking, the result would need adjustment for other liquids used

i bake them at 400 F, for 30 minutes, starting from there, if needs softer, add more minutes

when you roast/bake them, skin will peel easily, and you just mash it from there

(especially if you are going to freeze the puree later, it will produce water as well, right, so best is to roast the pumpkin instead steaming)