Preheat oven to 350°F (175°C). Toast pistachios on a baking sheet for 7–10 minutes. Cool and grind in a food processor. Set aside.

In a mixing bowl, whip 1 cup of heavy cream until soft peaks form (2-3 minutes). Transfer to another bowl and set aside.

In the mixing bowl, combine 1 cup of mascarpone cheese and 1/2 cup of powdered sugar until smooth. Fold in ground pistachios.

Gently fold whipped cream into the mascarpone mixture until fully combined. Be careful to maintain airiness.

In a saucepan, heat 1 cup of heavy cream until steaming. Remove from heat, add 8 ounces of chocolate, let sit for 5 minutes, then stir until smooth.

In dessert glasses, layer pistachio mousse and chocolate ganache, finishing with ganache on top.

Cover and refrigerate for at least 2 hours or overnight to set.

Garnish with crushed pistachios or chocolate shavings before serving and enjoy!