1. Preheat the oven to 350°F and butter (6-oz) ramekins or oven-safe bowls.
2. In a large bowl, whisk together the egg yolks, milk, lemon zest, lemon juice, butter, and salt. Next, add the flour and sugar and whisk until smooth.
3. Use an electric mixer to beat the egg whites in another bowl until it thickens and firm peaks form.
4. Gently fold the egg white mixture into the lemon mixture until smooth. Place the ramekins into a 9-by-13-inch baking dish.
5. Using a pitcher, pour hot water into the pan to reach halfway up the sides of the ramekins. Now distribute the batter evenly into the ramekins, filling them almost to the top.
   Tip: Placing the baking dish on a baking sheet makes it easier to carry.
6. Carefully place the baking pan in the oven and bake for 35 minutes, or until the cakes are lightly golden on top.
7. Using tongs, carefully remove the ramekins from the baking dish and let cool on a rack for about 10 minutes before serving.
8. Dust with Confectioners' sugar and serve with berries, if desired.

Recipe Tips: Make sure to use an electric mixer with the egg whites. If you do it be hand it will take longer, the mix will not get as firm but will still work. Boil 6 cups of water when you pre-heat the oven so it's ready.