Sift the polenta, flour, baking powder & salt into a bowl.
Tip the yoghurt, oil, lemon zest & juice into a jug and stir to combine.
Beat the eggs and egg whites with half the sugar until thick and creamy.
Fold in the dry ingredients.
Pour the batter into a greased & lined 2 pint loaf tin.
Bake for 40-45 minutes or until set & a skewer comes out clean.
Put the remaining sugar into a pan with 7 fl oz of water and the lavender heads.
Bring to the boil and then simmer for 10 minutes. Cool completely & then strain into a clean jug.
Whilst the cake is still warm, prick the top and drizzle over half the syrup, saving the rest to serve with the cake later.
Serve with extra syrup, raspberries, creme fraiche & a sprig of lavender.
The normal portions I use are 2 thin slices on each plate, overlapped for effect and then a drizzle of syrup around the slices with raspberries scattered over the top and a rounded tablespoon of creme fraiche to one side.