The secret to this bright, comforting dessert is a gentle water bath that lets it magically separate into two distinct layers as it bakes. You'll get a light, airy sponge cake on top and a rich, tangy custard hidden underneath. Fresh lemon zest and juice provide a refreshing citrus punch that balances the sweetness beautifully. It's an elegant yet surprisingly simple treat that works just as well served warm from the oven as it does chilled.
Prep
15 min
Cook
35 min
Total
50 min
Servings
6
Course
Dessert
Ingredients
2 tablespoons unsalted butter, softened, plus extra for pan(s)
½ cup plus 2 tablespoons (4⅓ ounces) sugar
⅛ teaspoon salt
3 large eggs, separated, plus 1 large white, room temperature
3 tablespoons all-purpose flour
2 teaspoons lemon zest plus ¼ cup juice (2 lemons)
1 cup whole milk
Instructions
1Mash the sugar, salt, and softened butter in a bowl using the back of a wooden spoon until the mixture looks crumbly. Mix in the egg yolks and flour until completely smooth. Gradually incorporate the lemon zest and juice, followed by the milk.
2Whip the egg whites in a stand mixer on medium-low speed for about 1 minute until they become foamy. Turn the mixer up to medium-high and continue whipping for 3 to 4 minutes until stiff peaks form.
3Carefully fold the whipped whites into the lemon batter until no large lumps are visible. Don't overmix, or you'll deflate the egg whites.
4Ladle the batter directly into your prepared baking pan or individual ramekins. Place the pan inside a larger roasting pan, then set it on the oven rack.
5Carefully pour boiling water into the roasting pan until it reaches halfway up the sides of the baking dish or ramekins. The water bath protects the delicate custard from cooking too fast and drying out.
6Bake for about 25 minutes, or until the center of the cake is set and springs back slightly when pressed lightly.
7Take the roasting pan out of the oven and let the cake rest in the hot water bath for 10 minutes before serving.
Notes
Serving: This dessert is incredibly versatile and can be served warm, at room temperature, or chilled.
Technique: Always ladle the batter rather than pouring it. This helps maintain the airy texture of the folded egg whites.
Science: The water bath provides insulation because water won't heat past 212 degrees Fahrenheit, creating a gentle, humid environment that keeps the custard creamy.