Once the frosting is ready, whip in the pistachio paste and almond extract - add more or less according to taste
Fill and Decorate
Level the cakes and cut each cake in half to make four even layers
Stack the layers, filling an even layer of pistachio Italian meringue buttercream in between each one
Cover the entire top and sides in buttercream and decorate how you like, I just used a palette knife to create little waves in the frosting - I like how that looks with Italian meringue buttercream as it's so glossy!