Food writer Carolyn Wyman wrote a regular feature for Philadelphia City Paper that probed the stories behind some of Philadelphia's most popular dishes. Alas, City Paper ceased publication. We're proud to continue Carolyn's fine work here at philly.com/food.

The name might make you expect a cross between apple and walnut pies.

But the apple walnut pie served at the Dining Car in Northeast Philadelphia and the eponymous Apple Walnut Cafe in Broomall actually consists of slices of apples folded into a cream-cheese filling that's topped with chopped black walnuts and cinnamon sugar and baked in a pastry crust.

The appeal of this pie/cheesecake hybrid also defies expectations.

"People come up to us all the time and say, 'I don't like cheesecake but I love this pie.' Or, 'I don't like walnuts, but I love this pie,'" says Dining Car co-owner and general manager Nancy Morozin.

Dining Car waitress Kim Dobron is a perfect example. A confirmed nut-hater, Dobron says she worked at the restaurant for two years before trying the pie. "Now I bring it to every party," she says.

Morozin attributes the pie's appeal to its restrained sweetness, and layering that offers the tastes and textures of cheese, apple, cinnamon, walnuts, and pie crust in almost every bite. The filling is also lighter than a traditional cheesecake's, so this dessert is rich without being heavy.

The pie's Dining Car home is a sprawling chrome-and-glass building with a taut menu (at least by 24-hour diner standards), a consequence of a from-scratch cooking philosophy. (Its signature creamed chipped beef is made from real top round; the chicken croquettes, with boneless chicken breast.)

The business was founded in 1961 by Morozin's Austrian-born father, Joe Morozin Sr., as the Torresdale Diner.

The apple walnut pie was introduced 20 years later by late baker and fellow Austrian Ed Petrasovits from his own recipe. And indeed the traditional Austrian cheesecake, called topfenkuchen, is lighter and less sweet than the American kind and features a dough, rather than a graham-cracker, crust.

Other German-Austrian foods on the Dining Car's menu catering to members of the nearby Cannstatter German-American club include pork and sauerkraut, linzer torte and the Christmas-only stollen, Pfeffernuesse, and springerle.

But none sell as well as the apple walnut pie.

Between whole 8-inch pies and slices, Morozin says she can they sell up to 20 a day and as many as 200 at Thanksgiving - so many that she rents freezer space from her ingredient suppliers to store them. (The pies are frozen after baking to firm up the cheesecake filling - otherwise it's "like pudding," says Morozin.)

When the apple walnut pie debuted, the diner sold its to-go desserts from an end-of-counter bakery case. Afterward, "so many people were coming in to buy the pie" and the Dining Car's also hugely popular Jewish apple cake "that our restaurant customers were having to wait to pay their bills." That explains the bake shop added to the end of the building in 1988.

When Morozin's sister, Judy, decided to open a cafe in a strip mall near her Delaware County home featuring Dining Car hits in 2014, there was no question about its name.

The Apple Walnut Cafe's brunch best-seller? A French toast riff on its namesake pie made from apple bread stuffed with apple walnut pie filling.

$3.50 per slice or $13.50 per whole pie at the Dining Car and Market, 8826 Frankford Ave., 215-338-5113, www.thediningcar.com, and $3.95 per slice or $15 per whole pie at the Apple Walnut Cafe, 2924 West Chester Pike, Broomall, 610-353-1384, www.applewalnut.com.