Adapted from “Baking Chez Moi,” by Dorie Greenspan (Houghton Mifflin Harcourt, 2014).
Tested size: 9 servings
INGREDIENTS
2 tablespoons unsalted butter, melted and cooled, plus more for the pan
3 medium juicy, sweet apples, such as Gala or Fuji, peeled
1/2 cup flour
1 teaspoon baking powder
2 large eggs, at room temperature
1/3 cup sugar
Pinch fine sea salt
2 teaspoons vanilla extract
6 tablespoons whole milk, at room temperature
Confectioners’ sugar, for dusting (optional)
DIRECTIONS
Preheat the oven to 400 degrees. Grease an 8-inch square baking pan with a little butter.
Slice the apples from top to bottom using a mandoline, Benriner or sharp knife, turning the fruit 90 degrees each time you reach the core. The slices should be about 1/16 inch thick: elegantly thin, but not so thin that they’re transparent and fragile. (If they’re a little thicker, that’ll be fine, too.) Discard the cores.
Whisk together the flour and baking powder in a small bowl.
Use a whisk to combine the eggs, sugar and salt in a large bowl for about 2 minutes, until the sugar has just about dissolved and, more important, until the eggs are pale. Whisk in the vanilla extract, then the milk and the melted, cooled butter. Add the flour mixture into the bowl; use the whisk to form a smooth batter.
Add the apples to the bowl; switch to a flexible spatula and gently fold in the apples, turning the mixture until each thin slice is coated in batter. Scrape the mixture into the pan, smoothing the top as evenly as you can. It will be bumpy; that’s its nature.
Bake (middle rack) for 40 to 50 minutes or until golden brown and puffed — make sure the middle of the cake has risen — and a knife inserted into the center comes out clean. Transfer to a rack and allow to cool for at least 15 minutes.
Carefully cut into 9 equal squares in the pan (being careful not to damage the pan); or unmold the slab onto a rack, flip it onto a plate so it is right side up and then cut it into 9 squares. Either way, give the squares a dusting of confectioners’ sugar before serving, if you’d like.
VARIATIONS: You can add a couple of tablespoons of dark rum, Calvados, applejack or Armagnac or a drop (really just a drop) of pure almond extract to the batter. If you have an orange or a lemon handy, you can grate the zest over the sugar and rub the ingredients together until they’re fragrant. You can also change the fruit. Pears are perfect, and a combination of apples and pears even better. Or make the cake with 2 firm mangoes — the texture will be different, but still good — or very thinly sliced quinces. Finally, if you want to make this look a little dressier, you can warm some apple jelly in a microwave and use a pastry brush to spread a thin layer of it over the top.