Use canned pumpkin puree instead of pumpkin pie filling for better flavor and texture., You can substitute spice cake mix to add extra warmth and flavor or gluten-free yellow cake mix for a gluten-free option., If using a smaller pan, increase baking time to ensure the center sets properly without over-browning edges., To store leftovers, cover pan with lid, plastic wrap, or transfer to an airtight container and refrigerate up to 4 days., To reheat, cover with foil and warm at 350ºF for about 15 minutes., To freeze, bake in freezer-safe pan, cool completely, wrap in plastic wrap and foil, freeze up to 2 months, thaw overnight in fridge before warming., A homemade pumpkin pie spice blend can be made with 1 tsp ground cinnamon, ½ tsp ground ginger, ¼ tsp ground nutmeg, and ¼ tsp ground allspice or cloves.