Raspberry cake filling: If you don’t wish to make the filling from scratch you could use a can of raspberry cake filling. (I prefer the Solo brand).For seedless raspberry filling, cook the raspberries with only water and lemon juice. Press the mixture through a sieve, and return the seedless strawberry juice/pulp to the pan. Add sugar and cornstarch and cook until thickened.Make ahead and Freezing instructions:Chocolate frosting will last for 2-3 weeks in the refrigerator and can be frozen for 2-3 months in a freezer-safe container. Thaw overnight in the fridge and bring to room temperature before frosting.To freeze the chocolate cake, cover each cooled cake layer with plastic wrap and place in a freezer-safe container or gallon bag. Freeze for up to 1 month. I think frozen cakes are easier to frost!