The Insane Lengths One DC Steak Restaurant Goes to in Order to Protect Its Secret Sauce

Confidentiality agreements and covert recipes are just the start at Medium Rare

Medium Rare's steak and fries. Photography by Scott Suchman

If you’re going to build your restaurant around one dish, it better be great—and it better be something no one can steal.

That was restaurateur Mark Bucher‘s thinking when he launched his steak-frites restaurant, Medium Rare, a decade ago in Cleveland Park. Its concept is minimalist: a prix-fixe menu ($22.95) of fresh bread, green salad, steak, fries, and of course, a special sauce. It wasn’t novel. Le Relais de Venis L’Entrecôte, the pioneering steak-frites restaurant from Paul Gineste de Saurs, launched in Paris in 1959. Its popularity spurred generations of replicas and knockoffs, including three separate L’Entrecôte restaurant groups from each of de Saurs’s children, and Bistro Régent, a current French rival who allegedly stole L’Entrecôte’s sauce and opened more than 90 locations. 

The business model spread to Washington with 1970s it-restaurant Le Steak in Georgetown. Newer incarnations (Béarnaise, Maxime, No. 82 Steakhouse) proved less successful, though DC is flooded with both chophouses and Fresh bistros offering some version of the dish. Bucher knew that a steak-frites concept in a steak-and-potatoes town would have to offer something exceptional. With seemingly simple components—grilled sirloin cap, crispy fries—the sauce must carry the restaurant. And no one besides him and business partner Tom Gregg could protect the secret. 

“You have to have the best of something. Otherwise, you’re off the radar,” says Bucher. “We knew we had to have a sauce with ‘come back’ quality.”

The duo spent a year sampling sauces, testing recipes with then consulting chef Cedric Maupillier (Convivial), and sampling more sauces. They scoured steakhouses in New York and Paris—including the original L’Entrecôte. “We tried to figure out what they do and the complexities because people were raving about it,” Bucher says. They sampled spoonfuls of creamy béarnaise, peppery au poivre, red wine, truffle, and the rich cognac-Dijon-mushroom found on steak Diane. Bucher, who founded (and sold) the local BGR the Burger Joint chain, also looked to the best patty shops for inspiration. Long days were spent in the test kitchen.

“We went through hundreds of versions. We tried combining sauces, separating sauces,” says Bucher. “We like to think of the ideal sauce as firing all the pleasure receptors in the brain, similar to ice cream but savory.”

The special steak sauce at Medium Rare
Medium Rare’s special sauce doesn’t have a recipe, but it does have a confidentiality agreement attached. Photograph by Scott Suchman

Then one day, voilà. They landed on a version of the sauce that cloaks the steak at all four Medium Rare locations in DC and Maryland as well as at Bucher’s new steak-and-fries-sandwich kiosk at Nationals Park. The delicious, bronze brew carries hints of mustard, cracked pepper, and something umami (chicken liver? mushrooms?). Bucher reveals it’s gluten-free but not dairy-free—and certainly not vegetarian-friendly. 

“It’s probably best to say that it’s a combination of au poivre and steak Diane with a little fettuccine Alfredo mixed in. Not literally, but it has those things,” he says.

Once the elixir was created, Bucher and Gregg set about protecting it—a tricky thing in today’s restaurant industry. Sharing recipe books is standard practice in kitchens, especially in a chain concept where high turnover of staff means those recipes can walk out the door. Bucher bested L’Entrecôte’s method, which was to guard the recipe in a bank vault. There is no written Medium Rare recipe, just cryptic parts divided among kitchens like fragments of culinary code. An outside company—Bucher is lock-lipped on the name—builds the sauce’s base and delivers it daily to the restaurants. Two cooks per location (“perfectionists,” says Bucher) are taught how to warm the sauce so it doesn’t break and finish it with “other ingredients.” Abstract color and flavor guides are provided for assistance. The cooks taste the sauce, and if it’s off, they try to correct it. If it can’t be corrected, they call Bucher.

The recent addition of a Medium Rare kiosk at Nationals Park potentially heightened security issues. Typically, when independent businesses partner with the ballpark, they hand over recipes and guidelines to mega-food provider Levy Restaurants to scale up for the 41,000-seat stadium. Not so for Medium Rare’s sandwich, which is essentially the steak-frites menu in handheld form. Roughly 70 quarts of ready-to-heat sauce are trucked to Nats Park for every home game. Bucher recently brought on former Redskins executive chef Jon Mathieson to oversee the project. The chef, who came from fine-dining kitchens like 2941 and BLT Steak, was the first person to be let in on the secret in more than a decade. 

All involved—the vendors, Medium Rare cooks, front-of-house staff—sign confidentiality agreements. Bucher says the fine print doesn’t hinder learning or future employment, just protects the trade secrets.

“It’s modeled after the Woodmont Grill [in Bethesda],” says Bucher. “People come and go, but nobody talks about how to make the spinach dip.” 

Food Editor

Anna Spiegel covers the dining and drinking scene in her native DC. Prior to joining Washingtonian in 2010, she attended the French Culinary Institute and Columbia University’s MFA program in New York, and held various cooking and writing positions in NYC and in St. John, US Virgin Islands.