• Adjust the oven rack to the lowest position and heat the oven to 325°F
• Place a dish towel in the bottom of a 13x9-inch baking pan. Great the small baking dish. NOTE: I used Bakers Joy non-stick spray. Set the small baking dish in the pan.

  Start a kettle of water to boil.

Egg whites:

• Using a hand-held mixer set at medium-low speed, beat egg whites in a large bowl until foamy, about 1 minutes. Increase the speed to medium-high and beat whites to soft, billowy mounds, about 1 minutes.
• Gradually add 6 tablespoons sugar and beat until glossy, stiff peaks form, 2 to 6 minutes. Set aside.

Batter:

• Whisk flour and cornstarch together in a small bowl. Using a hand-held mixer set at medium-high speed, beat butter, lemon zest, and remaining sugar in medium bowl until pale and fluffy, about 3 minutes. Scrape down sides of the bowl, as needed.
• Add the egg yolks and beat until combined, about 30 seconds.
• Reduce speed to low and slowly add flour mixture until combined, about 30 seconds.
• Add milk and lemon juice and beat until just combined.
• Using a rubber spatula, stir one-third of the beaten egg whites into the batter, then add the remaining whites. Gently fold the whites into the batter until no white streaks remain.

Bake the Lemon Pudding Cake:

• Scrape the batter into the prepared dish and smooth the top.

  Set the pan on oven rack. Taking care not to splash water into the dish, pour enough boiling water into the pan to reach halfway up the sides of the dish.
• Bake the cake until surface is golden brown and edges are set (the center should jiggle slightly when gently shaken. About one hour. NOTE: I checked on my cake at 50 minutes. While the cake wasn't very brown, the center was firmly set. End result: The cake was good!