Preheat the oven to 180 C / Gas 4. Grease a 23cm loose-bottomed cake tin and line with baking parchment.
Combine the yoghurt, melted butter, sugar, eggs, lemon juice and zest. Beat well using an electric whisk. Sift in the flour, baking powder, bicarb and salt. Stir gently with a wooden spoon till smooth. Tip into the prepared cake tin.
Bake for 50 to 60 minutes, or till a skewer inserted in the centre comes out clean. Cool in the tin for 15 minutes before removing from the tin.
Instead of butter, you can use 150ml of light-flavoured oil for this cake. If you really love lemon, be sure to use the lemon yoghurt and you can even add more lemon zest!