Mueller Chocolate Co. owner Glenn Mueller Jr. holds up a chocolate hand at the store in Philadelphia's Reading Terminal Market. (Sarah Maiellano /For The Washington Post)

“I have a question,” a sporty teenage girl asks. “Are chocolate-covered onions a thing?”

“They’re a thing here,” a Mueller Chocolate Co. employee answers.

“Oh. Really?” She pauses and looks at her friends. “Ew. . . . I’d like chocolate-covered strawberries, please.”

It’s a Saturday afternoon at Philadelphia’s popular Reading Terminal Market. A girls volleyball tournament is in town. Teenagers, parents and market regulars create human traffic jams in the lanes between the famous food hall’s 80 stalls.

On a busy day like this, Mueller Chocolate might serve 800 customers. Most come for the best-selling chocolate-covered pretzels, turtles and clusters — or, if they’re tourists, the chocolate cheese­steaks with a streak of white­chocolate “Cheez Whiz.” Fiends come for the 5-inch-tall Chocolate Tower. The macabre and irreverent come for the treats shaped like human body parts.

The brave come for the onion.

The Mueller family has been in the chocolate business since Glenn Mueller Sr. worked in the candy department at the long-gone Lit Brothers department store just a few blocks from Reading Terminal. Glenn Sr. took what he learned there and, starting in 1981, opened five of his own stores with his wife, Theresa, selling hand-crafted treats. “Dad learned what we still do today, the old-fashioned way, and I think that’s why we’re successful,” Mueller said. “Other companies push a button and make two tons of truffles.”

Chocolate-covered pretzels — along with turtles and clusters — are Mueller’s best-sellers. (Sarah Maiellano/For The Washington Post)

Today, Glenn Jr. — who sometimes calls himself Dr. Chockenstein — runs the show at Mueller Chocolate’s 1,500-square-foot stall, which serves 100,000 customers a year. Mueller isn’t a bean-to-bar chocolate maker, a trend he calls “millennial-speak for re-creating the wheel.” Mueller gets its chocolate from Peter’s Chocolate in nearby Lancaster County — a company founded by Daniel Peter, who along with Henri Nestlé was among the first to make milk chocolate in Switzerland about 150 years ago. “There’s a very distinctive chocolate flavor in Philadelphia,” Glenn Jr. said. “If you grew up eating chocolate here, it’s Peter’s. It’s creamy, with no astringent aftertaste.”

The sweet stuff takes hundreds of forms at the Mueller stall, none more infamous than the chocolate-covered raw onion. It was created in 1983, when the creator of a local children’s television show, “Double Muppet Hold the Onions,” asked the Muellers to make a chocolate-covered onion for Kermit to present to Miss Piggy. It turned Glenn Sr. and Theresa into Philadelphia celebrities — and earned wider fame in 2010 when Andrew Zimmern tried one on the Travel Channel’s “Bizarre Foods.” “The chocolate onion . . . is hideous, but we’ve been doing it for 30 years,” Glenn Jr. said. “It changed our trajectory.”

In 2013, Glenn Jr. developed an icon of his own — the Chocolate Tower. Everybody was selling chocolate-covered bacon, he recalled, “and I got tired of people asking us for it.” Instead, he stacked a chocolate-chip cookie, an Oreo and a house-made peanut butter cup to create what he called the Monstrosity of Chocolatey Proportions. After selling out frequently, the Monstrosity added a marshmallow and a Rice Krispies treat, and became the Chocolate Tower. It has been a big seller ever since.

A chocolate Liberty Bell is among the more orthodox offerings at Mueller Chocolate Co. (Sarah Maiellano /For The Washington Post)

As crowds of shoppers move past the Mueller stall, some stop to point, stare and whisper: “Oh, my goodness, what is that?” Well “that” is a display of kidneys (with candy kidney stones), brains, livers, eyes, hands, feet (with almonds as toenails) and noses — all edible, all chocolate.

It started, Glenn Jr. recalls, one Valentine’s Day in the late 1990s, when his mother decided that “these heart-shaped boxes are stupid.” She had a mold created based on a drawing of a human heart in her son-in-law’s medical school textbook. “We all thought she was crazy, but it’s been kind of the theme,” he said. “My mom is a pistol.” When the chocolate heart made national news, orders came in from around he world, he said, and demand hasn’t slowed down.

The heart is popular around Valentine’s Day, Mueller Chocolate’s busiest time of year. Chocolate livers are frequent 21st birthday presents. Brains and lungs have cheered up patients at nearby Thomas Jefferson University Hospital — or are given as thank-you presents to doctors. Sometimes, a slogan is written on the lungs package: It’s a gift for “the person who sucks the ever-living life out of you.”

But it’s not all organs and body parts: There are chocolate rats. The chocolate police kit (with a radio, baton, badge and handcuffs) and fireman kit (with a ladder, hat and fire truck) are usually given to new or retiring police officers and firemen, but handcuffs are sold by themselves too. “Some people like to think there’s more meaning to them than just a set of handcuffs, so we let them roll with it,” Glenn Jr. says.

Back in the middle of the packed market, Mueller employee Dan Bliss volunteers to taste-test the infamous onion and takes a brave bite. He chews and smiles. “It tastes like an onion,” he says. “Delicious! Can I make Brett eat it?” Glenn Jr. smiles and says “sure.” Brett Lane, another employee, samples the pungent confection: “That’s not bad!”

Maiellano is a Philadelphia-based freelance writer whose work can be seen at

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 For more dining and lodging recommendations, visit

If you go
Where to stay

Loews Philadelphia

1200 Market St.


A stone’s throw from Reading Terminal Market. Rooms from $179.

The Logan

1 Logan Square


Newly renovated and reopened with fanfare. Rooms from $227.

Where to eat

Reading Terminal Market

12th and Arch streets


Popular market with 80 vendors, including Mueller Chocolate Co. Open since 1892. Open 8 a.m. to
6 p.m. Monday to Saturday; 9 a.m. to 5 p.m. Sunday. Some stands, including several Amish vendors, closed Sunday and/or Monday.

Bank & Bourbon

1200 Market St.


Creative steakhouse-style restaurant in the Loews Philadelphia hotel with a popular bar across the street from Reading Terminal Market. Entrees start at $25.


640 N. Broad St.


House-made pasta, upscale pizza and more Italian fare just a mile away from Reading Terminal Market. Entrees start at $26.

What to do

Independence National Historical Park

Between Second and Seventh,
and Arch and Walnut streets


Sites in the park include Independence Hall, the Liberty Bell and the Benjamin Franklin Museum. Hours vary and reservations for some tours are advised. Free.

Philly From The Top

1650 Market St.


See all of Philadelphia from the 57th floor of the One Liberty building. $19. Open 10 a.m. to 10 p.m., daily. Adults $19, ages 11 and younger $14.


— S.M.