Step 1

Wash and hull the berries and gently puree them in a food processor, blender, or with a hand (stick) blender. You want them to be good and chopped up but not all liquid. You will need 1 cup of this puree for the cake and 2 tablespoons for the icing. This should make more puree than you need. However, if it doesn't, pour the puree into a measuring cup and add just enough water to make 1 cup plus 2 tablespoons.

Step 2

Preheat the oven to 350° F and lightly spray a 9X13-inch baking pan (or dish) with nonstick cooking spray.

Step 3

In a large bowl with a hand mixer (or in a stand mixer), mix together the cake mix, eggs, and vegetable oil until well combined. Open the gelatin and measure out 1 teaspoon into a small bowl and set aside for use in the icing. Pour the remainder of the gelatin and 1 cup of the strawberry puree into the batter and mix well.

Step 4

Pour the cake batter into the prepared pan and spread evenly. Bake for 30 to 35 minutes or until a toothpick inserted in the center comes out clean. Allow to cool completely before icing.

Step 5

In a large bowl with a hand mixer (or in a stand mixer) cream together the butter and cream cheese until well combined and all lumps are gone. Add the vanilla and mix well. Slowly add 3 cups of the powdered sugar separately, mixing well after each addition. Add 2 tablespoons of the strawberry puree and the reserved 1 teaspoon of strawberry flavored gelatin and mix well. Add additional powdered sugar if the icing is too thin. Frost by spreading over the cooled cake. Store in the refrigerator for up to 5 days.