This “cake” is essentially a free-form apple pie with a soft, puffy crust, baked in a standard casserole dish.

Steps

1. In a large bowl, mix together the flour, sugar, baking powder, and butter. Work this mixture with a pastry blender until it resembles coarse cornmeal.
2. Make a well in the center of the flour mixture and add the eggs and vanilla. Mix the eggs and vanilla slightly with a fork, then gradually whisk in the flour mixture. Work and knead until the mixture forms a coherent mass and is moist but not sticky. If sticky, add a little more flour and knead it in.
3. Cut the dough in half. Flatten the halves a bit to assist in rolling and wrap each half in plastic wrap or waxed paper. Allow to rest a few hours in the fridge.
4. Preheat the oven to 350 degrees. Butter a 9-inch-by-13-inch baking dish. Peel, core, and slice the apples, then toss them in a bowl with the lemon juice, sugar, and salt.
5. Take the dough out of the fridge and let it warm slightly for ease in rolling. Trying to keep within the parameters of the baking dish, roll out half the dough on a floured board. (The dough can be a bit sticky, so add a little extra flour as you flip the dough from one side to the other.)
6. Transfer the dough to a pastry sheet, waxed paper, or plastic wrap when it is approximately ¾ of the size you ultimately want and continue rolling it out to the final size. Lifting the rectangular sheet, invert it into the baking dish. (Do not fret if the dough rips or completely falls apart; you can always pat it into the pan and it will work out fine.)
7. Pile the apples high over the dough. Roll out the remaining dough half and place it over the apples.
8. Do not worry about holes in the top dough, as they just invite a sort of rustic appearance and allow for steam to escape during cooking. (I swear, the first time I made this cake, I threw it in the oven just to get rid of it, so vexed was I by the process. But it was the best ever.)
9. Bake the cake for 45 minutes, then check to see if the dough is done. I like to use a clear Pyrex pan so I can look at the bottom crust for color. Generally I remove the cake after 45 to 50 minutes, but let your oven be your guide.
10. Serve warm, with whipped cream if desired.