Preheat oven to 350°F. Butter a 9x13-inch baking pan.

Crack the egg into a mixing bowl and add the pumpkin puree; whisk together until uniform. Add the spice cake mix and pinch of kosher salt; mix together with a spatula until just combined. Transfer batter to the prepared pan and level it out with the spatula. Bake for 23 to 27 minutes, or until a cake tester inserted into the center of the cake comes out clean. (Test the cake early and add time as needed.) Set aside to cool completely, then cut into cubes.

Meanwhile, make the praline. Cover a baking sheet with parchment and set aside. Melt the butter in a 10-inch skillet over medium heat. Stir in the brown sugar, cinnamon, vanilla and a pinch of kosher salt. Cook until the sugar granules melt completely and the mixture turns syrupy, stirring often. (This may take 10-15 minutes. Be patient and do not adjust the heat.) Add the pecans; continue stirring for another minute until the pecans are well coated. Transfer the mixture to the prepared baking sheet and cool completely. Once cool enough to handle, crush the praline with a rolling pin, the flat side of a small pan or chop up with a knife.

Whip the heavy whipping cream on medium-high until medium peaks form (not too soft, not too stiff). Set aside. In another bowl, beat together the softened cream cheese, sour cream, sugar, and vanilla until smooth. By hand, fold about 1/3 of the whipped cream into the cream cheese mixture until well incorporated. Fold in the remaining whipped cream. If you wish, transfer the mixture to a piping bag or zip-top bag with the corner cut off.

Assemble the mini trifles in any type of glass or small mason jar. Start with a layer of cake, spoon or pipe on a layer of cheesecake mixture, then sprinkle on some praline. Repeat the layers once more.

Serve immediately or cover tightly with plastic wrap and refrigerate; serve chilled.