Preheat your oven to 350°F (175°C). Grease an 8-inch round baking pan with butter and line it with parchment paper.

In a medium bowl, sift together the all-purpose flour and baking powder.

In a large mixing bowl, cream together the melted butter and sugar using a hand mixer until light and fluffy.

Add the eggs one at a time to the butter-sugar mixture, blending well after each addition.

Slowly pour in the milk and rose water, stirring gently to combine.

Fold the sifted flour mixture into the wet ingredients using a spatula until just combined.

Gently fold in the roughly chopped pistachios.

Pour the batter into the prepared baking pan and smooth the top with a spatula.

Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean.

Once baked, let the cake cool in the pan for about 10 minutes before transferring to a wire rack.

When fully cooled, dust the top with powdered sugar or drizzle with icing.