Pistachio Sponge Cakes

1. In a large bowl, beat the softened butter and granulated sugar with a hand mixer for about 2 to 3 minutes.
2. Add the eggs, vanilla extract, pistachio paste, and a touch of green gel food coloring. Beat again for at least 3 more minutes, until the mixture is smooth and creamy.
3. Sift together the dry ingredients: cake flour, baking powder, baking soda, salt, and ground pistachios.
4. Add the dry ingredients in several additions, alternating with the buttermilk, and mix until just combined.
5. Fold in the chopped pistachios (optional, but they add great texture and flavor).
6. Divide the batter evenly between three 6-inch (15 cm) cake pans lined with parchment paper at the bottom.
7. Bake in a preheated oven at 330°F (165°C) for about 40 minutes, or until the centers are fully baked.
8. Let the cakes cool completely upside down on a wire rack. For a vibrant green color, you can gently trim off the brown crust on top.

Raspberry Insert

1. In a saucepan, heat the raspberries with the sugar and lemon juice over medium heat. Stir regularly until it just starts to bubble.
2. Add the cornstarch and stir well to thicken the mixture slightly.
3. Pour the mixture into two 12 cm (about 5-inch) cake pans lined with parchment paper.
   Let cool slightly, then freeze for at least 4 hours, or until fully set.

Whipped Pistachio Ganache

1. Melt the white chocolate, then stir in the pistachio paste.
2. Pour the hot heavy cream over the mixture and stir until smooth. Add the cold cream and blend briefly with an immersion blender.
3. Cover with plastic wrap pressed directly on the surface and refrigerate for at least 6 hours (or overnight).
4. The ganache should be very cold (around 41°F / 5°C) before whipping.
5. Just before assembling the cake, whip the ganache with the cold mascarpone in a stand mixer until it
6. becomes thick, smooth, and holds its shape.
7. You can add a touch of green gel food coloring to enhance the pistachio color.

Assembly and Decoration

1. Place the first pistachio sponge on a cake board set on a turntable. Wrap a tall strip of acetate sheet around the base to help with a clean, sharp build.
2. Pipe a border of whipped ganache around the edge, fill the center with more ganache, then place a frozen raspberry insert in the middle. Cover with more ganache.
3. Sprinkle in some chopped pistachios and a spoonful of pistachio spread if desired, then place the second cake layer on top. Repeat the process with the remaining layers.
4. Chill the assembled cake in the fridge or freezer for about 30 minutes to help it firm up.
5. Frost the entire cake with a smooth layer of whipped pistachio ganache using a spatula and a cake scraper.
6. Finish with a piped border using a piping bag and decorating tip, and top with fresh raspberries and chopped pistachios.