Melt the butter and let cool. Sift the flour into a bowl and mix in the sugar. Whisk in the eggs then gradually add the butter, salt, ground almonds, orange blossom water and lemon zest. Let stand for 1 hour.
Meanwhile, preheat the oven to 200°C (approximately 400°F) convection. Butter a 12-cup madeleine pan, fill with batter and bake for about 12 minutes, until light golden brown.