Preheat the oven to 180C/350F and greaseproof your cake tin.
Place the water, sugar and clove into a saucepan on medium heat, until the sugar has dissolved, allowing to simmer for approximately 3 minutes. Remove the clove and add the passionfruit pulp and allow to simmer for a further 3 minutes.
Pour into your cake tin and smooth out evenly and lay the sliced plums down into the syrup around the baking tin. Set aside.
Meanwhile, place the butter and sugar into a bowl and beat until combined. Add the eggs and vanilla extract and whip until well combined and fluffy.
Add the salt and Greek yogurt and fold until well combined and smooth.
Add the almond flour, polenta, plain flour, baking soda and baking powder and fold through until the batter is smooth.
Pour on top of the plums and spread out evenly.
Place in the oven and bake for 50 minutes or until golden brown on top and a skewer comes out clean in the center.
Remove and allow to cool for 5 minutes before flipping over onto a plate.
Allow to cool.
Serve with a little whipped cream or Greek yogurt if you wish.