Slice each cake into two layers so you end up with 4 layers of cake. Place one layer on a cake stand or cake plate.
Combine ¼ cup simple syrup and 3 Tbsp coconut vodka. Lightly moisten the cake layer with coconut vodka syrup using a pastry brush.
Spread a thin layer of raspberry preserves over moistened cake. Add about ⅓ cup frosting and spread into an even layer. Place another cake layer on top. Moisten cake with syrup, follow with raspberry preserves, and top with frosting. Repeat until you finish with the top layer.
Spread any remaining frosting on the sides of the cake, if desired. Otherwise, smooth the top of the cake and finish my smoothing the sides the cake with an offset spatula. Garnish the cake with fresh raspberries and pistachios.
Keep cake stored in the fridge until ready to serve. Let cake sit at room temperature for at least 45 minutes before serving to allow cake to soften.