To use fresh pumpkin or butternut squash, split the squash, remove the seeds and place cut side down on a baking sheet. Roast in a preheated 350 degree oven for 30 min to 1 hour, depending on size, or until meltingly tender. Scoop the softened pulp out of the shell and cool completely. One pound of squash yields about 12 ounces of cooked pulp, so use that to judge in recipes calling for canned pumpkin puree.