In a large bowl, beat together 1/2 cup water, 1 can of sweetened condensed milk, and 1 package of vanilla instant pudding mix. Mix until smooth and well combined.
Place the mixture in the refrigerator for about 5 minutes to allow it to set slightly.
In a separate bowl, beat 1/2 pint of heavy whipping cream until stiff peaks form. This will take a few minutes, so be patient.
Gently fold the chilled pudding mixture into the whipped cream until well combined. This will create a light, fluffy cream base for your trifle.
Cut one loaf of pound cake into small squares. The size of the squares can vary based on your preference, but bite-sized pieces work best for layering.
Using a glass trifle bowl, begin by adding a layer of the pudding mixture. Next, add sliced strawberries along the perimeter of the bowl. Layer the strawberries to make it look pretty from the outside.
Add a layer of pound cake squares on top of the pudding mixture. Then add a layer of strawberries. Continue layering the pudding mixture, cake, and strawberries. Continue layering the pudding mixture and cake. Tip: Feel free to add blueberries with the strawberries in your layers. I personally prefer for them to be used as part of the flag decoration on top; however, feel free to make it your own! Repeat the layering process until you run out of the cream mixture or the bowl is full. The goal is to have multiple, distinct layers of cream, cake, and fruit.
Once your trifle bowl is filled, top the dessert with an even layer of Cool Whip. This creates a smooth, white canvas for your patriotic decoration.
Create a flag design on top of the Cool Whip using strawberries and blueberries. The strawberries will form the red stripes, and the blueberries will represent the stars.
Allow the dessert to cool in the refrigerator for at least an hour before serving. This helps the flavors meld together and makes slicing easier.