Preheat the oven to 350 degrees Fahrenheit and spray a 6 ramekins (6 ounces each) with non-stick cooking spray.

Beat together the butter and sugar until combined.

Mix in the egg yolks one at a time.

Add in the milk, flour, lemon juice and lemon zest until combined.

In a separate bowl, beat the egg white until they are fluffy and form soft peaks.

Gently stir the egg whites into the batter.

Pour the batter evenly into the prepared ramekin dishes.

Place the ramekin dishes in a large pan and pour boiling water in the large pan until it goes up approximately 1/2 up the side of the ramekin dishes.

Bake for 40-50 minutes until the top of the cakes are golden brown and the center of the cake is set.  The center of the cake should gently spring back when touched.

Remove from the oven and remove the cakes from the water bath to cool on a wire rack.  Let the cakes cool for 15-20 minutes before serving.

Serve lightly dusted with powdered sugar and enjoy!