In a medium mixing bowl, whisk together the 1 (3.4 oz.) box vanilla instant pudding mix, 1½ cups cold whole milk, and 1 cup vanilla Greek yogurt or sour cream until smooth and the mixture begins to thicken. Set aside.
Cut the 14 ounces store bought angel food cake into 1-inch cubes and then evenly layer half of it into the bottom of the baking pan.
Spread about ⅔ of the 1 (21 oz.) can strawberry pie filling on top of the angel food cake, then layer the remaining angel food cake over the top of the strawberry filling.
Evenly spread the vanilla pudding mixture over the top of the angel food cake layer.
Then top it with the thawed 8 ounces Cool Whip, spreading it out to fully and evenly cover the pan.
Using a spoon, drop spoonfuls of the remaining strawberry pie filling over the cake and swirl it around a bit.
Chill in the refrigerator, uncovered, for 4 to 6 hours or even overnight for a more flavorful and moist cake. Refrigerating it will also help the layers to set. You can tent aluminum foil over the top of the cake if desired.
Right before serving, sprinkle with 3 tablespoons almond slivers. Enjoy!