Preheat the oven to 160°C.
Line a baking sheet with a perforated mat or baking paper.
In a large bowl combine the castor sugar and softened butter. Mix for 4-5 minutes until light, pale, and fluffy.
Sift in the icing sugar and mix for a further 3-4 minutes.
Sift in the cake flour, chickpea flour, wheat semolina, baking powder, cardamom, and mixed spice.
Using a spatula, mix until there are no dry bits, and the mixture is crumbly.
Pour in the melted butter and mix until the dough comes together. The dough will be soft to the touch and not sticky.
Using an ice cream scoop, scoop out 30 grams of dough and roll it into a ball.
Place the dough balls onto the lined cookie sheet, leaving space between them.
Place a slivered almond on each ball but do not press down.
Bake for 20 minutes until the tops are light and the bottoms are golden.
Let the Naan Khatai cool completely on the tray before transferring to a baking rack.