Preheat your oven to 170ºC (340ºF) while you prepare three 20 cm (8 in) baking pans. Line the bottoms with parchment paper and lightly grease the sides.

In a food processor, blend the unsalted pistachios until they reach a fine flour-like consistency. Sift this with all-purpose flour, baking powder, baking soda, and salt into a large bowl.

In a stand mixer, cream the room-temperature butter and granulated sugar together on medium speed for about 3 minutes until light and fluffy.

Integrate large eggs into the mixture, adding two at a time and mixing until fully combined. Scrape down the sides as needed.

With the mixer on low, alternate adding the dry and wet ingredients (sour cream, vegetable oil, and vanilla extract) until thoroughly incorporated.

Divide the batter evenly among the pans, smoothing the tops. Bake for 20-23 minutes until a toothpick comes out clean.

In a saucepan, combine frozen raspberries, sugar, lemon juice, and a splash of vanilla extract. Simmer for about 8 minutes until thickened. Stir in cornstarch mixture to reach desired consistency and cool completely.

For the buttercream, cream together softened butter and sift in raspberry powder along with powdered sugar. Mix in whole milk gradually until fluffy.

Once the layers are completely cool, assemble by spreading buttercream and raspberry jam between the layers, refrigerating briefly.

Complete the cake with a crumb coat of buttercream and finish with a final layer. Garnish with fresh raspberries and chopped pistachios.