Preheat oven to 150°C (300°F) and line two large baking sheets with parchment paper

Grind pistachios with 50g icing sugar in food processor until fine powder forms (2-3 minutes pulsing)

Whip egg whites to soft peaks in clean bowl, gradually add caster sugar until stiff glossy peaks form

Gently fold pistachio-sugar mixture into meringue in three additions using large metal spoon

Divide mixture between prepared baking sheets, creating two 20cm circles with slight wells in center

Bake for 2 hours 30 minutes until firm and dry, cool in oven with door ajar

Puree 200g raspberries until smooth, strain through fine-mesh sieve to remove seeds

Whip cream with vanilla to medium peaks, gradually fold in raspberry puree

Assemble by spreading raspberry cream between meringue layers

Garnish with remaining 50g whole raspberries and serve within 2 hours