Preheat the oven to 350°F (175°C). Grease two round cake pans and dust with flour.

Pulse pistachios in a food processor until finely ground.

In a mixing bowl, cream butter and sugar until fluffy. Add eggs one at a time, mixing well after each addition. Stir in vanilla and ground pistachios.

In another bowl, whisk together flour and baking powder. Gradually mix dry ingredients into the batter, alternating with milk.

Divide batter between pans and bake for 25-30 minutes until golden brown. Cool completely before removing from pans.

For raspberry filling, heat raspberries, sugar, and lemon juice in a saucepan until thickened. Cool before using.

For French buttercream, whip egg whites until soft peaks form; gradually add sugar until stiff peaks form. Mix in softened butter until smooth.

Assemble the cake by layering one cake onto a plate; spread raspberry filling and buttercream on top before adding the second layer. Frost top and sides.