Preheat oven to 180 degrees celsius (170 fan-forced).
Grease a non-stick springform round cake pan (approx 20-22cm diameter) and set aside (you can use a non-springform pan, but I find they work best).
Sift the plain flour and baking powder into a large bowl.
Add the sugar and salt and stir to combine.
In a separate bowl, whisk the ricotta, eggs, vanilla and melted butter together until well combined.
Add 1/2 of the ricotta mixture to the dry ingredients and gently mix to combine.
Add the remaining ricotta mixture and gently mix to combine.
Add 1 cup of the raspberries are very gently fold through.
Pour the mixture into the prepared cake tin and place the remaining raspberries on top.
Cook for 50-60 minutes or until a skewer inserted into the middle comes out clean.
If you find the cake is browning too much, gently place a sheet of foil over the top and return to the oven.
Leave the cake to cool completely in the pan.
Remove from pan before serving and dust with icing sugar.
Store the cake in an airtight container in the fridge for up to 3 days (bring it to room temperature before serving).