Preheat an oven to 350°F (180°C). Grease a 13-by-9-inch (33-by-23-cm) baking pan.
To make the crust, in the bowl of an electric mixer fitted with the flat beater, combine the quick bread mix, egg and melted butter and beat on low speed until the ingredients come together, 1 to 2 minutes. Transfer the mixture to the prepared pan and spread out evenly. Press the crust down until it feels compact (using the back of a measuring cup can help).
Wash and dry the mixer bowl and beater.
To make the filling, in the mixer bowl, combine the cream cheese and pumpkin butter and beat on medium speed until smooth, about 1 minute. Add the eggs, vanilla, melted butter and cinnamon and beat until combined, about 2 minutes. Add the confectioners’ sugar and beat well, about 2 minutes. Spread the filling over the crust. Transfer to the oven and bake for 40 to 50 minutes. Do not overbake; the center should still be a little gooey. To test for doneness, gently shake the pan; you should see a slight jiggle in the center. Transfer the pan to a wire rack and let cool for at least 20 minutes, then cut into bars. Makes 16 bars.