Preheat oven to 350°F.

Line the bottom of an 8-inch nonstick cake pan with parchment paper.

In a mixer fitted with a paddle, cream together the butter and superfine sugar until light and fluffy.

Add the eggs one at a time, then add the ground pistachios and almonds.

Add the orange juice, orange zest and rosewater, and mix well. Using a rubber spatula, fold in the flour; do not overmix.

Scoop the mixture into the cake pan, and bake until the top is firm and a light golden brown, about 40 minutes.

Lightly cover the top of the cake with foil and continue baking until a toothpick inserted into the center comes out dry, about 10 minutes more.

Allow the cake to cool in the pan for several minutes, then remove and cool on a rack.

When the cake is cool, mix the confectioners’ sugar and lemon juice together in a small bowl, and pour over the cake.

While the frosting is still soft, sprinkle with the whole shelled pistachios. Allow the icing to set for 30 minutes before serving.