Making Berry Bliss Sheet Cake is straightforward if you follow these easy steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
2. Mix Dry Ingredients: In a large bowl, whisk together the flour, baking powder, and salt.
3. Cream Butter and Sugar: In another bowl, cream the softened butter and granulated sugar until light and fluffy.
4. Add Eggs and Vanilla: Beat in the eggs one at a time, then add the vanilla extract and mix until well combined.
5. Combine Mixtures: Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Mix until smooth.
6. Fold in Berries: Gently fold in the mixed berries, taking care not to crush them.
7. Pour Batter: Pour the batter into the prepared baking pan, spreading it evenly.
8. Bake: Bake in the preheated oven for 30-35 minutes or until a toothpick inserted in the center comes out clean.
9. Cool: Remove from the oven and let the cake cool in the pan for about 15-20 minutes before transferring to a wire rack to cool completely.
10. Make Frosting: In a bowl, whip the heavy cream with powdered sugar until soft peaks form.
11. Frost the Cake: Once the cake is completely cool, spread the whipped cream frosting over the top.
12. Garnish: Decorate with additional fresh berries on top for a stunning presentation.

These steps will guide you through making this incredible Berry Bliss Sheet Cake effortlessly, ensuring that you create a dessert that will delight everyone.