This coffee magic cake bakes into three delicate layers from one simple batter: a light sponge top, creamy custard center, and soft, dense base with rich coffee flavor in every bite.
Separate 4 eggs into yolks and whites with an egg separator. In a large bowl, whisk the egg yolks with ¾ cup (150 g) sugar using a hand mixer until pale and creamy.
Add 1 cup (120 g) 00 flour and mix until fully incorporated. Pour in ½ cup (120 g) melted butter, mixing continuously until combined.
Pour in 1 cup (250 ml) milk and 1 cup (250 ml) lukewarm coffee, whisking until smooth. The batter will look very thin.
In a separate bowl, beat the egg whites until stiff peaks form. Gently fold them into the batter using a balloon whisk or spatula. The batter should stay foamy and slightly lumpy.
Pour the batter into a parchment-lined 8x8-inch (20x20 cm) baking dish.
Bake in a preheated oven at 340°F / 170°C (300°F convection / 150°C fan) for 50 minutes, until golden with a slight wobble in the center.
Let the coffee magic cake cool completely, then refrigerate for at least 2 hours before slicing. Dust with powdered sugar just before serving.
Notes
Let the Coffee Cool: I always use lukewarm coffee so the eggs stay smooth and the batter blends properly. The Batter Should Look Thin: It may seem too runny at first, but that is exactly what creates the three layers while baking. Fold Gently: I like to leave some fluffy bits of egg white visible because they help form the airy sponge layer on top. Chill Before Slicing: I find the layers become cleaner and creamier after a few hours in the fridge. Dust Before Serving: I always add the powdered sugar at the end so it stays light and pretty on top.