Line an 8-inch baking pan with parchment paper or grease well with butter.
In a mixing bowl, combine flour, cornmeal, salt, and baking powder and set aside.
In another mixing bowl, whisk sugar and eggs using an electric whisk until the mixture becomes pale. Now, add yoghurt, lemon juice and zest, oil, and butter; mix well until combined.
Pour the egg mixture over the cornmeal mixture, mix well. Pour all the batter into the baking pan and bake for 40 minutes. To know if the cake is fully baked, insert a toothpick in the centre of the cake; if it comes out clean (nothing on it), the cake will be good.
Allow the cake to cool down, then sprinkle some powdered sugar on top of it.
Using fine or coarse cornmeal will only affect the cake's texture, not the taste; however, I prefer to use coarse cornmeal because I like the gritty texture.
You can sprinkle orange zest on top of the cake instead of powdered sugar for an extra orange flavour (if you like).
If you like it nutty, just sprinkle some chopped nuts of your choice (such as almond or walnut) on top of the batter before baking it.