Preheat your oven according to the directions on your cake mix package. In a large mixing bowl, prepare the batter using the cake mix, eggs, oil, and water as specified. Mix until smooth and well blended, ensuring there are no lumps.

Divide your prepared cake batter equally into four separate bowls. Add pink, yellow, green, and blue food coloring to each bowl, stirring gently until you've achieved vibrant pastel shades.

Pour each colored batter into the greased baking pans, spreading it evenly to create thin layers. Bake in the preheated oven for 15 to 20 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, remove the cake layers from the oven and let them cool in the pans for about 10 minutes. Then, transfer the cakes onto a wire rack to cool completely.

In a large mixing bowl, whisk together the two boxes of instant vanilla or white chocolate pudding mix with 4 cups of cold milk. Beat until the mixture is thick and smooth, about 2 minutes.

Once your pudding has set, gently fold in the thawed whipped topping with a spatula.

In a trifle dish or a large glass bowl, start layering the dessert by placing a layer of cake cubes at the bottom. Top with a generous layer of the pudding mixture and then a layer of whipped topping.

Carefully decorate the top of your assembled Easter Trifle Dessert with mini chocolate eggs, pastel sprinkles, and edible flowers if desired.

Refrigerate your Easter Trifle Dessert for at least 1 hour before serving.