Preheat the oven to 180 C / Gas 4. Grease and line a deep 20x30cm cake tin with baking parchment.
For the cake:
In a mixing bowl beat the butter and sugar together until light and fluffy. Beat in the eggs, one at a time, mixing well after each addition. Sift in the flour and add the cinnamon and nutmeg. Once well mixed, add the yoghurt, vanilla extract and blackberries. Pour the cake mixture into the prepared tin and smooth the top.
For the crumb topping:
In a bowl rub the butter into the flour and sugar until fine breadcrumbs form. Using your fingers clump into large crumbs and scatter over the top of the cake.
Bake in the preheated oven for 30 to 40 minutes or until a skewer inserted into the centre comes out clean. Remove from the oven and allow to cool for 1 hour before slicing and serving.
After going blackberry picking and collecting 2kg of the things, I was delighted to find this tray bake recipe. I used wholemeal self raising flour and it is delicious. It will be perfect in squares for back to school packed lunches. The crumble topping is a great addition adding a lovely texture and crunch. - 02 Sep 2014