Grease a Madeleine tin with some butter. Whisk the eggs with the sugar, honey, vanilla and salt in a large bowl for 5-8 minutes until very pale and at least doubled in volume, using an electric whisk.
Sift over and fold in the flour and baking powder, then the melted butter and the lemon zest from both lemons then add the juice from one lemon then mix until fully incorporated.
Cover and chill for an hour or two, or overnight. Give the chilled mixture a good stir and fill the moulds by three quarters with a heaped teaspoon
Preheat the oven to 240C/220C fan/gas 9. Place the cakes in the oven, immediately turn the temperature down to 220C/200C fan/gas 7 and bake for 4 minutes.
Then turn the oven down to 190C/170C fan/gas 5 and continue baking for another 4 minutes until domed and risen in the centre, the mixture is set and the edge of each cake is golden.
Run a knife around the edge of each one. Leave them to cool on a cooling rack.
Once cooled, make the icing. Mix the juice of the final lemon with 100g of icing sugar until the mixture is thick but runny.
Add the icing to a piping bag and cut the end off and move the piping bag across the madelienes until each madeliene has at least three lines of icing on it.