1. Preheat the oven to 350° degrees F.
2. Cut your jack-o-lantern into large wedges. Place the wedges skin side up on a lightly oiled baking sheet. Bake for approximately 90 minutes, or until the pumpkin wedges are fork tender.
3. When the pumpkin is cool enough to handle, scoop the flesh out of the skin into a bowl, then mash it or whirl it in a food processor. If the purée is a bit watery, cook in a saucepan over medium heat until some of the moisture has evaporated.
4. Let cool, then portion into freezer bags or containers and freeze. The purée can be defrosted quickly in the microwave or by placing the frozen bag or container into a bowl of hot (but not boiling) water. Use by itself to help with canine constipation or diarrhea (check with your vet for the amount appropriate for your dog), or—more pleasantly—try it in this recipe for Pumpkin Cheese Cups.