When someone with a food allergy walks into one of Philly’s busiest restaurants, what happens next?

On any given day, 100 people walk into Center City’s busiest restaurant with a declared food allergy or intolerance.

Each arrival to Parc on Rittenhouse Square sets off an intricate dance of highly choreographed steps between the front and back of the house: Big yellow tickets go flying, clean pans and cutting boards come out of hiding, meats are sliced and prepped from scratch.

The elaborately layered allergen protocol at Parc — and Starr Restaurants’ 34 other full-service establishments — is the most detailed I’ve encountered in three years of researching gluten-free restaurants. It’s one reason why I’ve found the restaurant group has such a strong reputation in the gluten-free community and beyond. “We are not taking a single chance,” says Jenna Velella, who developed the protocol as the company’s vice president in charge of strategic initiatives.

» READ MORE: The definitive guide to Philly’s gluten-free restaurants and bakeries | Craig LaBan

A growing awareness of food allergies has generated the need for a strong and consistent protocol, says Velella, who notes that at least 10% of Starr’s customers now specify a dietary issue; gluten-free is the most prevalent dietary restriction, followed by allergies to nuts, and then seafood, according to Velella. At a restaurant like Parc, which can serve more than 1,000 diners on a single weekend day, that’s a significant number. “We get so many requests for modifications, it’s just the status quo,” she says.

Guests can scout their food options even before they arrive, as Parc is one of several Starr restaurants that posts menus online detailing all available gluten-free and vegan dishes.

The first step for staff once guests are seated is identifying any restrictions; diners should let the restaurant know of their dietary needs either in advance, when making the reservation, or before ordering. Once an issue is noted, the staff will also clarify any specific details: For example, is a guest eating gluten-free by preference, where some cross-contamination is allowable, or is it a more serious health issue, such as an allergy or celiac disease, an autoimmune disorder which requires gluten to be avoided entirely? “We train our team to pretty much default to [treating any allergy as] serious,” Velella says. But “it’s necessary to understand how far we need to go and to design something that fits what they need for the entire table.”

Once a dietary restriction is confirmed, the restaurant’s “allergy alert process” is triggered. In addition to a flag in the restaurant’s ordering software, the server fills out an enormous, school-bus yellow card headlined “ALLERGY ALERT!” that details a diner’s specific allergies, their table, and their seat position. The card is handed off to a manager, who then delivers it to the kitchen, so the staff knows an allergy precaution is coming, often before an order is even placed: “Seat two at table 22 is celiac,” for example.

The service staff is trained on the allergens contained in every dish, “but nobody guesses tableside,” Velella says. A direct conversation about each order is still required between a server or manager and the kitchen to verify allergens. “There is no assuming.” For this reason, Parc’s famed bread basket is not usually delivered until after an order is placed, Velella says, and only if guests are comfortable with bread on the table; even then, it’s placed as far as possible from the gluten-free diner.

The yellow allergy card is attached to all of the table’s orders throughout the entire meal regardless of whether a specific dish has gluten or not. Every item ordered for that guest is modified for the allergy and clearly marked with the allergen so anyone on the kitchen staff involved in that dish knows to be in “allergy mode.”

The kitchen will modify any dish within reason, unless modifications compromise the integrity of a dish — the French onion soup, for example, which, aside from the crouton, has a flour-based roux at its base. In this situation, another dish would be recommended. Once an order is confirmed, the chefs start à la minute preparations from scratch with fresh mise-en-place and freshly cut, unmarinated steaks and fish, using clean cutting boards, utensils, and pans. When a gluten-free order comes in for the popular veal escalope, for instance, a piece of meat from a separate batch is cut and seasoned by cook with just-washed hands and new gloves, then cooked in a fresh pan without the usual dredge in flour. The mushroom cream sauce with spring onions is then built in the pan à la minute, as always. “Most of our sauces are already naturally gluten-free,” Velella says.

The finished dish is delivered separately by someone with freshly washed hands, preferably a manager. When presenting the dish, a server will announce the specific modifications rather than simply say it’s gluten-free, especially if the same dish has been ordered by another diner, or if other dishes have been modified for the table to respond to different allergies. If there are shared items on the table, any potential allergens will be announced.

Servers are expected to check back within two minutes of tables getting food to make sure everything is as expected, although this is routine for all orders. It’s just one more standard precaution built into a restaurant whose daunting volume can present challenges when exceptions on dishes must be made for diners’ safety. “It’s so busy that there’s always fear about dealing with allergies. How do you keep track of it all?” says Velella. “This system is how we keep track. Once we’re in motion, Parc is usually all about repetition and high velocity. But this is how we force built-in disruptions to pause and stop ourselves.”

At a restaurant as busy as Parc, all that coordinated fuss behind the scenes is worth it, especially if diners who stress out about eating in restaurants due to a dietary restriction can relax and enjoy a meal knowing their concerns have been heard, and are carefully being accommodated.