Preheat the oven to 180 C / Gas 4. Grease a 20x30cm deep traybake tin and line with baking parchment.
For the cake:
In a mixing bowl beat the butter and sugar until light and fluffy. Beat in the eggs, one at a time, mixing well after each addition. Sift in the flour and add the nutmeg. Once well mixed, add the yoghurt, vanilla extract, lemon zest and cherries. 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 35 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.