Set aside a few strawberries for decoration. Hull the remainder and cut them in half or into quarters if they are quite large.
To create four even cake layers, first trim the tops off the cakes with a cake leveler or large serrated knife so that they are 1½ inch thick. Next, cut each cake in half so that you have four ¾ inch layers.
Spread a little frosting onto your serving plate or cake stand and attach the first cake layer onto it.
Brush the berry syrup over the cake layer.
Fit a piping bag with a large round tip, and half fill with frosting. Pipe a layer of frosting onto the cake (approximately 1 1/3 cups). If you don’t have a piping bag, spread a ¼ inch layer of frosting onto the layer with an offset spatula.
Arrange a mixture of the berries (approximately 2/3 cup) over the frosting layer.
Place the second cake layer on top. Brush the second layer with syrup and repeat the process from the first layer of adding the frosting and berries.
Add the third layer of cake, brush with syrup, spread with frosting and arrange more berries on top.
Place the final layer on top and crumb coat the whole cake by covering it in a very thin layer of frosting. Chill for 15 minutes.
Spread the remaining frosting over the cake with an offset spatula. To create a swirl finish, place the cake on a turntable and hold the offset spatula against the side of the cake. Turn the cake continuously as you slowly run the knife up the side of the cake. Repeat on the top starting in the middle and work out towards the edges.
Arrange the remaining berries and mint sprigs on top of the cake. The cake can be refrigerated for one day. Bring to room temperature before serving.