Prepare the Cake Batter:

1. Preheat oven to 180°C (350°F). Grease and line two 8-inch cake tins.
2. In a large bowl, cream butter and sugar until light and fluffy.
3. Beat in vanilla bean paste and add eggs one at a time, mixing well.
4. In a separate bowl, whisk flour, baking powder, salt, and ground pistachios.
5. Gradually fold dry ingredients into the wet mixture until just combined.

2. Bake the Cakes:

1. Divide batter evenly between prepared tins.
2. Bake for 25-30 minutes, or until a skewer inserted in the center comes out clean.
3. Cool in tins for 10 minutes, then transfer to a wire rack to cool completely.

3. Make the Pistachio Buttercream:

1. Beat butter until smooth.
2. Gradually add sifted icing sugar, beating until light and fluffy.
3. Mix in pistachio cream and lemon juice until well combined.

4. Assemble the Cake:

1. Level cake layers if needed.
2. Place one layer on a plate and spread raspberry jam over it.
3. Add a layer of pistachio buttercream.
4. Place the second cake layer on top and repeat.
5. Frost the top and sides with remaining buttercream.

5. Decorate:

1. Garnish with fresh raspberries, chopped pistachios, and mint.
2. Optionally, dust with icing sugar for an elegant finish.