Add the two cans of pumpkin to the bottom of the slow cooker and spread evenly. Cover the pumpkin with the box of cake mix evenly. Add the butter on top. Cover and cook on high for two hours. After two hours, stir everything together until mixed well. Recover and cook for an additional one hour.
For the Cream Cheese Filling
Beat the cream cheese, butter, and vanilla until blended. Gradually beat in the confectioners' sugar until smooth.
To Assemble the Pumpkin Trifle
Add a scoop of the cooled cake into a glass or serving dish. Spoon cream cheese frosting on top of the cake. Repeat. Sprinkle final layer of cream cheese with cinnamon or pumpkin pie spice.
Make sure the cake is cooled before adding the filling or it will melt into a soupy mess.
You can serve this Pumpkin Trifle as one big trifle or in individual glasses.
Add brandy or rum to the cake layers for a boozy treat.
This dessert needs to be refrigerated because of the cream cheese filling.