Pre-heat the oven to 320F/160C and line a loaf tin (I used a 9 x 5 inch tin) with baking paper.
Cream together the butter and sugar with a handheld mixer. Whisk in the eggs one by one, then stir in the yoghurt. Fold through the flour, then stir in the lemon zest and juice.
Pour a layer of cake batter into the prepared baking tin, then spoon and slightly swirl some of the lemon curd over it. Scatter some of the blueberries on top, then pour in the rest of the batter. Finally, dot the rest of the lemon curd on top and swirl it a little again and lightly press in the rest of the floured blueberries.
Adapted from this recipe from BBC Goodfood.
I first published this post on 20th June 2014. Updated with new photos, writing, and a video.