Lemon Custard Cake for Two

1 egg, separated
1/2 cup sugar
1/3 cup milk
2 tablespoons flour
2 tablespoons lemon juice
1 1/4 teaspoon grated lemon zest (reserve 1/4 teaspoon of zest)
1/8 teaspoon salt
Whipped cream, optional

Preheat the oven to 325F (163C).

In a large mixing bowl, beat the egg yolk until light and fluffy.  Add in sugar, milk, flour, lemon juice, lemon zest, and salt.  Mix until smooth.

In a second mixing bowl, beat the egg white until stiff peaks form, and then gently fold into the lemon mixture.

Pour the mixture evenly into two ungreased custard cups (6 ounce size).

Using an 8 inch baking pan, place the custard cups into the pan, and then pour boiling water into the pan to until the water comes up on the cups about 1 1/2 inches.

Bake for 40-45 minutes, or until an inserted knife comes out clean, and the cakes are golden.  To serve, place a dollop of whipped cream and garnish with the remaining lemon zest.