In a large mixing bowl, whisk together the instant vanilla pudding mix and 2 cups of cold milk until the mixture thickens, about 2 minutes.

Gently fold in 1 cup of sour cream into the pudding mixture using a spatula, being careful to avoid over-mixing.

In a trifle dish or large glass bowl, layer half of the angel food cake cubes evenly.

Sprinkle half of the mixed berries over the first layer of angel food cake cubes.

Carefully pour half of the creamy pudding mixture over the layer of berries.

Repeat the layering process with the remaining angel food cake cubes, followed by the rest of the mixed berries, and pour the remaining pudding mixture on top.

Spread a generous layer of whipped topping over the final pudding layer.

Drizzle caramel or berry sauce over the whipped topping if desired, and add extra berries for garnish.

Cover the dish with plastic wrap and refrigerate the cake for at least 2 hours, or preferably overnight.