Always use pure pumpkin purée instead of pumpkin pie filling to avoid too much sweetness or texture issues., Use spice cake mix instead of yellow to get warm fall spices., Fresh pecans add flavor and texture; toasting them intensifies flavor., Do not stir butter into cake mix; the layering effect creates the magic texture., Bake times might vary slightly with pan materials; the center can be slightly jiggly but will set when cooled., Refrigerate leftovers tightly wrapped for up to four days., For a nut-free version, omit pecans or substitute with toasted pumpkin seeds., Do not substitute evaporated milk with water; whole milk with cream can be used if evaporated milk unavailable., To serve warm, reheat individual pieces in microwave or warm whole dish covered at 325°F.