Magic Lemon Custard Cake Recipe

Preheat your oven to 325°F (165°C) and place a rack in the middle position. Line an 8×8 inch baking dish with parchment paper for easy removal and even baking.

Separate the eggs carefully, placing the whites in the bowl of a stand mixer fitted with a whisk attachment ensuring no yolk contaminates the whites. Add the cream of tartar if using, and whisk on medium-high until stiff peaks form, about 3 to 5 minutes. Transfer the whipped whites to another bowl and set aside.

Without cleaning the bowl, add the yolks and whisk on medium-high speed until foamy, about 1 minute. Gradually drizzle in the sugar while continuing to whisk until the yolks become creamy and pale, around 2 to 3 minutes. Add salt, melted butter, and vanilla extract, and mix for another 1 to 2 minutes until fully incorporated.

Swap the whisk attachment for the paddle attachment. On medium-low speed, add the sifted flour and mix until smooth. Next, mix in the lemon juice and zest, then slowly pour in the whole milk while continuing to blend until the batter is well combined. Use a silicone spatula to scrape down the sides and bottom of the bowl to ensure uniform mixing.

Remove the bowl from the mixer. Gently fold one-third of the whipped egg whites into the batter using a silicone spatula to lighten it. Fold in the remaining whites in two more additions, mixing delicately to keep the airiness intact. It’s okay if some small pockets of egg whites remain visible.

Pour the batter into the prepared baking dish and bake for 45 to 55 minutes. The top should be lightly golden, and the center will jiggle slightly when the pan is gently shaken.

Let the cake cool completely at room temperature. Once cooled, cover it and refrigerate for at least one hour, preferably overnight, to set the custard texture fully.

Remove the cake from the pan using the parchment paper, dust with powdered sugar if desired, cut into 9 squares, and serve chilled or at room temperature for a refreshing, light dessert.