In a small saucepan, combine the glaze ingredients and bring to a boil. Stir for 3 minutes, then remove from heat. Set aside.
Preheat the oven to 350°F (180°C). Butter and flour an 8x9-inch (18x22 cm) baking pan.

In a mixer, beat the egg yolks with the sugar until light and slightly pale. Add the cardamom, rose water, milk, and oil, and beat for 1 more minute.

Stop mixing. Add the flour and baking powder mixture, and gently fold in with a flexible spatula. Then add the ground almonds or pistachios and the apple, and fold again.

In a separate bowl, beat the egg whites with a whisk until they form soft peaks. Gently fold the egg whites into the batter with a spatula, using light, circular motions from top to bottom, until the batter is smooth and airy. Pour the batter into the prepared pan and bake for 30–35 minutes (I baked it for 40). Check for doneness by inserting a knife into the center—if it comes out clean, the cake is done.

Remove the pan from the oven and place it on a wire rack. While the cake is still warm, evenly spread the glaze over the top and let it soak in and cool completely.
Cut the cake into pieces and sprinkle with pistachios and almonds.