Preheat oven to 350F degrees. Spray 9x13-inch baking dish with nonstick cooking spray.
Give the strawberries a good rinse then gently dry them with a paper towel. Remove the stems and dice.
Put strawberries into a plastic Ziploc bag and start crushing them up using a rolling pin or other heavy object. This will probably take you a minute or two.
In the bowl, combine cake mix with strawberry gelatin powder. Mix until combined.
Then stir in oil, eggs and water.
Once that is combined, add in 1 cup of the smushed strawberries. You will want to gently stir those in by hand.
Then pour batter into prepared baking dish.
Bake for about 30-33 minutes. Oven times do vary so to make sure it is done, stick a toothpick in the center, if it comes out clean, it is good to go.
Allow cake to cool completely before adding frosting.
For the frosting:
Using an electric mixer, mix together the softened butter and softened cream cheese. Mix until smooth, creamy and lump-free.
Then mix in powdered sugar, vanilla extract and milk. Mix until smooth and creamy.
Slather frosting onto cooled cake. Put the cake back into the refrigerator for about an hour to help the frosting set up.
Then slice and serve! I like to top each piece of the strawberry cake with a slice of fresh strawberry .
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Notes
If there are any leftovers, you'll want to cover it and put into the fridge.
It's really important the cream cheese is fully softened. If not, it will stay lumpy as you try to mix it.
If you are not a fan of cream cheese frosting, just leave it out and it will be a buttercream frosting. Adjust milk as necessary in the frosting to get the consistency you enjoy.