Tarte Tatin

1. FOR THE DOUGH: Process flour, sugar, and salt together in food processor until combined, about 5 seconds. Scatter butter over top and pulse until mixture resembles coarse cornmeal, about 15 pulses. With machine running, add egg and continue to process until dough just comes together around processor blade, about 12 seconds.
2. Turn dough onto sheet of plastic wrap and flatten into 6-inch disk. Wrap tightly in plastic and refrigerate for 1 hour. Before rolling dough out, let it sit on counter to soften slightly, about 10 minutes. (Dough can be wrapped tightly in plastic and refrigerated for up to 2 days or frozen for up to 1 month. If frozen, let dough thaw completely on counter before rolling it out.)
3. Roll dough into 14-inch circle on lightly floured counter, then transfer to parchment paper–lined baking sheet; cover with plastic and refrigerate until needed.
4. FOR THE APPLES: Adjust oven rack to upper-middle position and heat oven to 425 degrees. Melt butter in 12-inch ovensafe nonstick skillet over medium-high heat. Stir in sugar and cook until mixture is light golden, 2 to 4 minutes.
5. Off heat, place first apple quarter cut side down, with end touching skillet wall. Continue to arrange apples, lifting each quarter on its edge and placing next apple quarter on its edge, so that apples stand straight up on cut edge. Fill skillet middle with remaining quarters, halved if necessary. Cook apples over medium heat until they are lightly golden and caramel is darkly colored, about 6 minutes, turning apples over halfway through cooking.
6. Off heat, slide chilled dough over apples in skillet. Being careful not to burn fingers, fold back edge of dough so that it fits snugly into skillet. Transfer skillet to oven and bake tart until crust is golden brown, about 20 minutes, rotating skillet halfway through baking.
7. Using potholder (skillet handle will be hot), remove skillet from oven. Let tart cool in skillet for 30 minutes. Run small knife around edge, place inverted serving platter (or cutting board) over top and gently flip tart onto platter, using mitts or kitchen towels if skillet is still hot. Scrape out any apples that stick to skillet and put them back into place on tart.
8. FOR THE TOPPING: Using stand mixer fitted with whisk, whip cream and sour cream on medium-low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1 to 3 minutes. Serve individual portions with dollop of topping.

Make sure that the caramel doesn’t get too brown before adding the apples in step 5; it should be just golden. Be sure to let the tart rest for 30 minutes before serving, or it will likely break into pieces when you unmold it.

ASSEMBLING TARTE TATIN
1. Arrange apples around edge of skillet, lifting them on their edges so that they stand up, being careful not to burn your fingers. Arrange remaining apples in middle of skillet.
2. Using paring knife, turn apples onto their uncaramelized sides halfway through cooking.
3. Off heat, slide prepared dough off baking sheet over skillet and tuck dough edges gently up against skillet wall.
4. Place serving platter over skillet and hold it tightly against skillet. Invert skillet and platter and set platter on counter. Lift skillet up off platter, leaving tart behind.