Ask for potato filling in certain corners of Pennsylvania — ours included — and you’ll get a blank stare. Settle down for a Thanksgiving meal in Berks County, though, and you won’t even have to ask for it.

Potato filling’s always been there.

“I’m responsible for the potato filling on Thanksgiving, but both of my daughters know how to make it,” said Susan Dice, 71, of Womelsdorf, Berks County. “My mother made it and my grandmother made it.”

Potato filling is a good way to get rid of stale bread, something warm to pile onto the plate beside the turkey and cranberry sauce. As far as recipes go, it’s about as complicated as grilled cheese. If you’ve ever mashed all your Thanksgiving sides into one spoonful, you sort of get the idea.

“It’s basically a combination of mashed potatoes and stuffing,” said Zach Brown, a lifelong Berks County resident who runs the Berks County Eats website.

In Pennsylvania, the warm, creamy, carb-laden side dish is so cherished, it beat out pineapple stuffing and baked corn as the state’s most Googled Thanksgiving recipe, according to a 2014 New York Times story. (Stuffed artichokes topped New Jersey’s searches, closely followed by ricotta cheesecake.)

Pennsylvania-based food historian William Woys Weaver has said that it dates back to the 1700s but that a detailed origin story is lost to time. Most people in Berks and some surrounding counties assume the dish, like many others there, has Pennsylvania Dutch roots that may trace back to Germany.

Whatever its genesis, the side comes together in many ways — some recipes start with ready-made mashed potatoes, some call for boiling them at the start — but it’s always anchored by potatoes, white bread, and butter. Lots of butter: A Pottstown-sourced recipe in the Washington Post calls for 20 tablespoons (that’s 2½ sticks) to make a batch large enough for 10 servings.

The butter is divvied up between the potatoes and the bread, which often gets toasted in a skillet with onion and celery. Eventually, the starches are folded together in a casserole dish, topped with dots or a drizzle of butter, then browned in the oven until a crust forms. As it cooks, the hunks of butter-saturated bread melt into mashed potatoes. A finishing sprinkle of herbs (parsley, sage) or spices (paprika, nutmeg, poultry seasoning) varies from region to region and cook to cook.

“There are as many great recipes for potato filling as there are grandmothers in Berks County,” Brown said.

Susan Dice grew up in Lebanon County, to the west, and her potato filling was always covered in saffron.

“I think they used saffron to make it look yellow,” she said. “I love the saffron flavor, though. That’s the way I make it. That’s not a Berks County thing. They flavor it with pepper or parsley. I think that’s the Berks County way.”

At Deitsch Eck (Dutch Corner), a traditional Pennsylvania Dutch eatery in Lenhartsville, the owner’s aunt, Nancy Stump, was busy preparing potato filling on the kitchen stove one rainy morning earlier this month. Along with the boiling potatoes and day-old rolls, Stump was sautéing celery, onions, and parsley. Soon, she’d add some milk and stir it all together.

Though simple, there are potato-filling taboos.

“A lot of places don’t serve it, and when they do serve it, they would use instant potatoes,” Stump said. “We never use instant.”

Deitsch Eck was opened in the 1930s by Johnny Ott, whose traditional Pennsylvania Dutch “hex” art still adorns the walls. Owner Steve Stetzler often has Amish customers, which he said is rare for a private restaurant. Potato filling has likely always been on the menu, he said, and always will be.

“We knew coming in here, of course, that we had to have it,” said Stetzler, who bought the restaurant in 1997. “We hardly ever do mashed potatoes. It’s always potato filling.”

Stetzler said some customers add a little hot bacon dressing to the filling, a Deitsch Eck special. Last Thanksgiving, they sold 300 pounds of potato filling takeout.

Brown, 34, said his family always buys a tray of the traditional dish from Zion Lutheran Church in Womelsdorf, which churns it out for a yearly holiday fund-raiser. Dice is one of the cooks, and often, they take orders for Christmas as well.

"This year, we made 207 two-pound trays,” Dice said. “Sales were a little down.”