Preheat the oven to 350°. On a stove, pour about 6 cups of water and bring to a boil. Reduce water to simmer.
Lightly grease 4 ramekins (approximately 4.5" in diameter) and set aside.
Prepare two medium bowls. In the first, whisk the sugar with the flour. In a second bowl, whisk the egg yolks with the butter until well blended. Whisk in the milk, lemon juice and lemon zest. Pour the lemon mixture into the sugar mixture and whisk until smooth.
In a large bowl with high sides, beat the egg whites with the salt until firm peaks form. Gently fold the egg whites into the lemon mixture. Pour the batter into the prepared ramekins and transfer them to the roasting pan. Place the pan in the oven and pour in enough hot water to reach halfway up the sides of the ramekins.
Bake the pudding cakes for 35-40 minutes or until they are puffy and golden on top. Using tongs and a slotted spoon, gently transfer the ramekins to the cooling rack. Cool for 20 minutes.
Lightly sprinkle powdered sugar over micro flowers. Place gently on cooled cakes and dust with more powdered sugar. Alternatively, unmold the cakes by running a sharp knife around the edge and inverting the ramekin onto a small plate. Pile micro flowers on top.