in a large bowl, combine cake mix and gelatin, add pureed strawberries, eggs, oil, and water; beat at medium speed with an electric mixer until smooth. pour into prepared pans, and bake for 20 minutes, or until a wooden pick inserted in the center comes out clean.
let cool in pans for 10 minutes, remove from pans, and cool completely on wire racks.
For the Frosting; In a large bowl, beat butter, and cream cheese at medium speed with an electric mixer until creamy. beat in 1/4 cup of the strawberry puree, and the strawberry extract. Gradually add confectioners sugar, beating until smooth.
Spread frosting in between layers and on top and sides of cake. garnish with strawberries, optional.