Preheat the oven to 350°F. Lightly grease an 8" square baking pan., To make the topping: Melt the butter in a large frying pan, add the apple, and cook over medium heat 2 minutes., Add the Pie Filling Enhancer or flour, sugar, and cinnamon and cook for 2 minutes, until the apples start to caramelize. Add the walnuts and remove from the heat., In a saucepan set over a low burner, combine the caramel and cream; bring to a simmer, stirring until smooth and melted (alternatively, heat the caramel and cream in the microwave). Transfer the melted mixture to the prepared baking pan. Spoon the apple mixture over the caramel., To make the pudding: Beat the butter and sugar until smooth., Add the eggs one at a time, beating well after each addition., Fold in the flour, salt, and cinnamon., Spoon the mixture over the apples, spreading to level. Cover the pan securely with aluminum foil and set it in a larger roasting pan. Add enough hot water to the roasting pan to come halfway up the sides of the 8" pan., Bake the pudding for 65 to 70 minutes, until a toothpick inserted into the center comes out clean., Remove it from the oven, and let it rest for 15 minutes before serving., Storage information: Serve warm, or at room temperature; ice cream or whipped cream are always a good option. Refrigerate any leftovers.