Preheat oven to 170*c. Lightly spray a 23cm cake tin, using a piece of grease-proof baking paper on the bottom In a medium bowl combine the flour, brown sugar, baking powder and salt.
In a separate bowl combine the Grove Extra Virgin Avocado Oil, milk, eggs, vanilla paste and lemon & orange zest.
Gently combine the wet ingredients with the dry ingredients and finally fold through the blackberries and pour mix into the prepared cake tin.
Bake for approx 1 hour or until a toothpick removes cleanly from the centre of the cake.
Remove from cake tin and rest on a cake rack for 15 mins.
Place the cooled cake onto a cake stand and garnish with the remaining fruit and a dusting of icing sugar.