Butter an 8 inch round cake pan and line it with parchment paper. Make sure that your parchment paper is longer than the sides to catch any syrup that may leak over (you will also want to put a catch tray under your pan in the oven.)
Prepare a small cup of water by the side of the stove with a pastry brush. Put the sugar and water for the caramel in a large pan. Make sure the sugar has been coated by the water. Bring the sugar to the boil (without stirring, but rotate pan if needed). If sugar has separated on the side of the pan use your wet pastry brush to brush down the sides of the pan making sure the sugar doesn't crystalize.
Once your sugar is a nice golden color add the butter and stir with a wooden spoon. Stir until incorporated and turn off heat. The caramel should now be smooth and a golden brown.
Pour the caramel into the lined cake pan and quickly swirl it around the base so that it coats the entire bottom surface completely.
While that is cooling, zest 2 oranges and set aside. Cut off the top and bottom off of each orange and peel off the skin using a sharp knife following the natural circular shape of the orange. Be sure to remove as much of the skin, seeds and membrane as possible.
Cut the oranges into thin slices, removing more of the skin and membrane as well. Using your nicest pieces, lay slices on top of the caramel next to each other. Do not overlap them, but fill any holes with small orange pieces. Make sure you cover the whole surface.
Preheat your oven to 350° F.
Starting on your cake batter you will use a standing mixer to cream the butter and sugar together. Add the eggs one at a time and mix until incorporated. Stir in the orange zest and blossom water.
In a separate bowl mix the flour, polenta, baking powder and salt. Slowly pour that mixture into the wet ingredients and mix until combined.
Place the batter into your cake tin (mine was so thick I used an ice cream scoop). Take care to not move the oranges much. Level the batter with an offset spatula or knife and place in the oven, over a catch tray. Bake for 40 minutes or until a cake tester/toothpick come out clean.
Remove from the oven and let cool for 5-10 minutes. Turn the cake out onto a platter or serving dish.
Combine the marmalade and water for the glaze in a saucepan and heat for 1-3 minutes. Sieve the glaze and brush on top of your cake.
If you wish to make the whipped cream, add the ingredients into a large bowl and whisk for 5 minutes by hand. Make sure the cream forms stiff peaks, but do not over whisk or you will create a butter (like mine).