Preheat oven to 180 degrees. Grease and flour a 6 inch pan - I used my heart shaped pan.
In a bowl, whisk the semolina, baking powder, sugar and cardamom powder till sell combined. Add the oil, mango pulp and rosewater and fold in till completely moist. Leave the batter for around 10 minutes for the liquid to get absorbed by the semolina.
Pour into the prepared pan and make even on top. Sprinkle the pistachios.
Bake for 25-30 minutes till a skewer comes out clean.
Allow to cool in the pan for five minutes. Flip onto a cooling rack and cool completely before serving.
Notes
I found the cake to be on the sweeter side since I have used canned mango pulp. You may skip or reduce the sugar in this case. But if using fresh mango pulp, you may need more sugar.