Heat this over medium heat whisking until thickened (1-2 minutes.) Remove from heat and stir in the butter and vanilla; cool in the fridge for 2 hrs. Then fold in the Cool Whip.
To make puff pastry for a Napoleon cake, grate the cold butter into flour and salt. Then mix together the sour cream, vinegar, egg, and vanilla and stir this into the flour until a dough forms.
Preheat the oven to 430°F. Divide the dough into 9-10 pieces.
Roll out each piece to a 10″ circle over a well-floured surface. Place over a sheet of foil and stack until the rest of the dough is rolled out.
Bake each layer until golden (6-8 minutes.) Cool.
To Assemble the Napoleon cake, stack the cake layers between pastry cream reserving one puff pastry layer for the cake crumbs.
Frost the sides and top then garnish all over with crumbs.
Allow the cake to soak in the cream overnight. Napoleon cake is best the next day before slicing and serving.
Nutrition per serving
Serving: 1sliceCalories: 364kcalCarbohydrates: 33gProtein: 6gFat: 23gSaturated Fat: 14gPolyunsaturated Fat: 1gMonounsaturated Fat: 6gTrans Fat: 1gCholesterol: 100mgSodium: 275mgPotassium: 120mgFiber: 1gSugar: 12gVitamin A: 764IUVitamin C: 1mgCalcium: 81mgIron: 1mg
