Mix together cake mix and dry Jello in mixing bowl
Add eggs, oil, water and 3/4 cups mashed strawberries.
Beat with mixer until blended.
Pour into two greased and floured 9" pans.
(Important - be sure to grease your pans well and then flour them, or they will not come out of the pan.)
Bake for 27-30 minutes, or until toothpick inserted comes out clean.
Cool for 10 minutes in cake pans, then place on wire racks and cool completely.
While cake is baking, smash 1 cup strawberries until smooth (you may want to use a blender - I used my Pampered Chef chopper and just got them good and smashed.)
Place strawberries in saucepan over medium heat and bring to a boil, stirring frequently.
Continue to cook until mixture is reduced by about half (for about 12-18 minutes.)
Remove from heat and cool completely. (I put them in a small bowl in my refrigerator to cool more quickly.)
Beat butter with electric mixer until fluffy.
Add in 1 cup powdered sugar until blended.
Add 2 tablespoons of cooled strawberry puree and vanilla extra, beat into butter mixture until blended.
Repeat with another cup of confectioners sugar, then an additional 2 tablespoons of strawberry puree.
Add one more cup of confections and another 2 tablespoons strawberry puree.
Beat in remaining 1/2 cup confectioners sugar until light and fluffy.
Spread frosting on cake and enjoy!