Create the caramel. Heat a 9 x 13 or circular baking pan in the stove top using medium heat. Pour-in the granulated sugar and let stand until the sugar melts (or turns into caramel). You may want to stir the sugar once in a while to make sure that everything is equally distributed within the area of the baking pan. Set aside.
Create the custard. Combine milk, egg yolks, and sugar in a mixing bowl. Stir the ingredients until everything is properly distributed.Pour the custard mixture on the baking pan with caramel. Set aside
Create the cake. In a clean mixing bowl, beat the egg yolks then gradually add the sugar. Continue beating for about 2 minutes. Put-in a small amount of cake flour alternately with the milk diluted in water and mix well. Do this procedure until the cake flour and milk diluted in water are completely used up. Put-in the lemon rind then beat until texture is smooth. Set aside.
Create the meringue. Beat the egg whites using an electric mixer until texture becomes bubbly (use high speed). Add the cream of tartar then continue to beat until texture becomes fluffy (about 3 to 4 minutes in high speed). Gradually add the sugar then continuously beat until meringue is shiny and firm.
Fold the cake mixture into the meringue until well blended
Pour the folded cake and meringue mixture over custard mixture in the baking pan.
Preheat oven to 350 degrees Fahrenheit
Pour about 6 to 8 cups of hot water on a roasting pan (with rack) then place the cake pan on top of the rack.
Place the roasting pan that contains the cake pan with all the mixtures in the oven and bake for about 60 minutes or until the toothpick test indicates that the cake is ready.
Remove cake from the oven and allow the temperature to cool down.
Transfer to a serving tray then refrigerate for at least an hour.
Serve chilled, share and enjoy!