Preheat oven to 350 degrees. Gather your ingredients so that you have everything close at hand on the counter or table.
Prepare Your Ingredients
Using a fine-edged grater, zest one large lemon. Squeeze the juice of 1-2 lemons with a citrus juicer to equal 1/3 cup lemon juice.
Melt the butter in a microwave-safe bowl for 10-15 seconds.
Carefully, separate the egg whites from the egg yolks, using two separate bowls.
Prepare the Cake - Pudding
In a large mixing bowl, sift together the granulated sugar, all-purpose flour and salt.
Stir in the melted butter, lemon zest, and freshly squeezed lemon juice.
In a glass measuring cup whisk together 3 egg yolks and whole milk with a fork. Add this to the lemon mixture, stirring well to combine.
In another mixing bowl, whisk the remaining egg whites until soft peaks form. You may do this by hand or with a mixer. Gently fold the egg whites into the lemon batter.
Pour the batter into the square or round ungreased cake pan. Place this pan inside a larger pan. Set on a middle oven rack.
Pour hot water into the larger pan until it is about 1 inch deep. Bake in preheated oven for 35-40 minutes.
Cake should spring back when touched and will have a creamy lemon pudding beneath the cake. Allow to cool on a wire rack. You may serve this cake warm (after about 40 minutes) or cover and refrigerate for 2 or more hours to serve cold.
Dust with powdered sugar before serving. If desired, scoop spoonfuls of the cake and pudding into small dessert bowls or cups. Serve with a dollop of whipped cream. Serves 6.
*Unless otherwise indicated, all butter on this recipe site is salted.