Blueberry Cake

INGREDIENTS:

4 large organic free range eggs
80g demarera sugar
190g soya margarine
100ml extra virgin olive oil or soya oil (or any other healthy oil you might have such as canola oil)
160 ml skimmed milk
seeds of one vanilla pod
300g wholemeal flour
100g buckwheat flour
a pinch of sea salt
grated zest of 2 limes and 2 lemons
600g fresh blueberries

METHOD:

Pre-heat [...]