Put your cake ring on a cake pad or anything that you will be able to transfer in the fridge after assembly.
If you have acetate roll, roll it inside the 18 cm cake ring, tape it to make sure it does not move during assembly.
Put your 16 cm large sponge in the middle of the ring.
Cut strawberries in half vertically, add halved strawberries all around the ring, inside facing the roll.
Pipe the diplomat cream between the strawberries to make sure there are no gaps in the cake.
Put diplomat cream on top of the sponge cake all the way above the strawberries.
Add freshly cut strawberries in the middle.
Add another layer of diplomat cream.
Add the second sponge cake on top.
Add the last layer of diplomat cream.
Finish with freshly cut strawberries to decorate the top of your cake.
Let the cake rest in the fridge for at least 4 hours. That will allow the cream and gelatin in it to stabilize and become more solid.