Step 1: Bake the Cake: Preheat oven to 350°F (175°C). Prepare cake batter according to package instructions or homemade recipe. Bake in a 9×13-inch pan for 25–30 minutes, or until a toothpick inserted in the center comes out clean. Cool completely on a wire rack. Cut cake into 1–2 inch cubes.

Step 2: Prepare Whipped Cream: In a chilled mixing bowl, beat heavy cream until soft peaks form. Add powdered sugar and vanilla extract, then beat until stiff peaks form.

Step 3: Prepare the Berries: Rinse berries and pat dry. Slice strawberries if needed and optionally sprinkle with 1 tbsp sugar to macerate for 10 minutes.

Step 4: Assemble the Trifle: In a large clear trifle bowl, layer one-third of the cake cubes at the bottom. Spread one-third of the whipped cream over the cake layer. Arrange a layer of red berries (strawberries and raspberries) on top. Repeat layers until all ingredients are used, ending with whipped cream on top. Decorate the top with a combination of blueberries and sliced strawberries for a patriotic design.