Preheat the oven to 180 degrees C (350 degrees F/Gas Mark 4) and grease a 20cm (8 inches) diameter springform tin, then line the base with baking parchment.
Add the 200g (7 ounces) of sugar and water to a large saucepan and bring to the boil, simmer for 1 to 2 minutes until the sugar has dissolved and add the orange slices. Simmer for 15 minutes until a little softened. Arrange in the base of the tin, starting in the center, slightly overlapping the slices and working your way out to the outside.
Beat the 225g (8 ounces) sugar and butter in a bowl until the mixture is light and pale. Add the eggs, one at a time, beating well after each addition. Bash the cardamom pods in a pestle and mortar and extract the seeds. Then bash the seeds to a fine powder and add to the butter, sugar mix along with the ground almonds, zest and polenta and stir gently to combine.
Pour the mixture into the prepared tin, place it on the middle shelf of the oven to bake for about 50 minutes or until a skewer comes out clean. Remove from the oven and allow to cool on a wire rack until almost fully cooled.
Prepare the syrup by placing the saucepan back over a over a medium heat, stir in the 2 teaspoons rosewater and bring to a steady simmer. Simmer for 5 to 6 minutes until slightly reduced.
Once the cake has cooled turn out onto a stand, pour over the syrup and leave to cool completely.
When the cake has cooled completely whisk together the mascarpone, cream, honey and 1 tablespoon rosewater until soft peaks form.
Serve on plates with a dollop of the rose mascarpone, sprinkle with the pistachio nuts, pomegranate seeds, and drizzle with any of the remaining syrup.
if you don’t have a pestle and mortar you can pop the cardamom seeds in a zip lock bag and bash with a rolling pin.