Instead of a layer of frosting, try using this strawberry cake filling! Put some of your frosting in a piping bag and make a ring of frosting around the edge of the cake. This will hold your strawberry filling into place. Then spoon a generous layer of strawberry filling into the middle. Use a rubber spatula or offset spatula to spread it all the way to the frosting, adding more as needed. Add your next layer of cake on top. You may want to do a crumb coat of frosting before this, to prevent cake crumbs from mixing with the strawberry sauce.  Make sure you cool cake layers completely before decorating, or it will start to melt the frosting.  Repeat with as many strawberry cake layers as you have. You can also spoon it on top of a layer of buttercream frosting for a creamy filling.