Step 1

1 Preheat the oven to 400 degrees

Step 2

2 Grease an 8-inch square baking pan with a little butter

Step 3

3 Slice the apples from top to bottom using a mandoline

Step 4

4 Benriner or sharp knife, turning the fruit 90 degrees each time you reach the core

Step 5

5 The slices should be about 1/16 inch thick: elegantly thin, but not so thin that they’re transparent and fragile

Step 6

6 (If they’re a little thicker, that’ll be fine, too

Step 7

7 ) Discard the cores

Step 8

8 Whisk together the flour and baking powder in a small bowl

Step 9

9 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

Step 10

10 Whisk in the vanilla extract, then the milk and the melted, cooled butter

Step 11

11 Add the flour mixture into the bowl; use the whisk to form a smooth batter

Step 12

12 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

Step 13

13 Scrape the mixture into the pan, smoothing the top as evenly as you can

Step 14

14 It will be bumpy; that’s its nature

Step 15

15 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

Step 16

16 Transfer to a rack and allow to cool for at least 15 minutes

Step 17

17 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

Step 18

18 Either way, give the squares a dusting of confectioners’ sugar before serving, if you’d like

Step 19

19 VARIATIONS: You can add a couple of tablespoons of dark rum

Step 20

20 Calvados, applejack or Armagnac or a drop (really just a drop) of pure almond extract to the batter

Step 21

21 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

Step 22

22 You can also change the fruit

Step 23

23 Pears are perfect, and a combination of apples and pears even better

Step 24

24 Or make the cake with 2 firm mangoes — the texture will be different, but still good — or very thinly sliced quinces

Step 25

25 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