Preheat your oven to 175°C (350°F) and finely grind the shelled pistachios in a food processor until they resemble coarse flour.

In a mixing bowl, combine the ground pistachios with all-purpose flour, baking powder, and salt.

In a large mixing bowl, beat the softened unsalted butter and granulated sugar together using an electric mixer until light and fluffy.

Slowly add the eggs one at a time, mixing well after each addition, then incorporate the milk, oil, vanilla extract, and optional almond extract.

Gently fold the dry mixture into the wet ingredients using a spatula, ensuring not to over-mix.

Divide the batter evenly among three greased 8-inch round cake pans and bake for 22-25 minutes.

Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

While the cake layers cool, whip the heavy cream until soft peaks form, then gradually mix in the powdered sugar and mascarpone cheese.

Once cooled, place one cake layer on a cake stand and spread a generous amount of frosting on top, then repeat with remaining layers.

Frost the entire cake, ensuring a smooth finish, and sprinkle the chopped pistachios over the top.

Refrigerate the cake for at least 2 hours before slicing.