Preheat the oven to 180°C. Grease and line a 13 cm x 28 cm loaf tin with baking paper.
Place the sugar and eggs in a bowl and whisk until creamy. Add the yoghurt, oil, flour and baking powder and mix until smooth, then stir in the vanilla and lemon zest. Gently stir in three-quarters of the blackberries, the pour into the prepared tin. Top with the remaining berries and the almond flakes. Bake for 40-45 minutes or until pale golden and a skewer withdraws clean.
Cool in the tin then turn out onto a rack to cool completely. Serve as it is or dusted with icing sugar or with a dollop of yoghurt or a scoop of gelato.
