The Eyebrow-Raising Ingredient That Makes This Classic NJ Pizza a Local Legend

Hyperlocal pizza traditions are no longer just local—many have gone national. I’ve met Seattle natives who swear the best pizza in the country is New Haven apizza, and one of my favorite pizza shops in New York is a Chicago-style joint known for—get this—their thin crust.

I spent countless hours of my youth in Jersey slice shops, refining my skills in pizza identification: a square vs. a grandma slice, margherita vs. cheese. Now I'm an adult with a tendency toward culinary fixations as well as a more refined pizza palate developed while working in Brooklyn pizzerias like Roberta’s and Barboncino. I constantly think about the next trend to take this pizza-loving country by storm, and right now my money is on a pizza subculture within a subculture (a "pizz-ception," if you will). AND it’s from my home state. I’m talking about Trenton’s own mustard pie.

A mustard pie is exactly what it sounds like, a fantastic slice of NJ pizza with the zip and heat of spicy brown mustard spread just below the cheese. It adds depth and complexity, accomplishing more than many more bombastic pies ever manage to, without being overpowering.

Now for those who have alarm bells ringing just at the thought of this combination, I remind you that tomato and mustard are a savory dynamic duo. The sweet acidity of the tomato brightens the earthy heat and slight bitterness of mustard. French chefs knew this when they developed tarte à la tomate, a savory pie made with tomatoes, Gruyère, and Dijon mustard. And need I remind you of the two brightly colored bottles that sit on every diner table and are used to top fries, burgers, and dogs, often in combination?

Where Does the Mustard Pizza Come From?

Of course, making a mustard pizza isn’t as simple as squirting some of the yellow stuff onto your dollar slice. The recipe is an evolution of the tomato pie, a Jersey icon with roots in Trenton, New Jersey and surrounding areas.

The tomato pie is reminiscent of New Haven coal-oven pizza with a thin, well-done crust. The unique thing about these NJ pies is that they eschew the typical pizza construction: Instead of building pies by topping dough with sauce and then cheese, they go dough first, then cheese, then blots of sauce. The result is a tomato-forward experience that brings the acidity and sweetness of the juicy red fruit to the forefront. A pizza befitting a state known for its tomatoes, if you ask me.

Though I haven’t uncovered the full backstory behind the momentous innovation of adding mustard to the classic tomato pie, I do know it took hold when Bill Schuster of Schuster’s—a now-defunct Trenton pizza shop—began drizzling spicy brown mustard onto his pies. Against all odds, people fell in love with the tangy bitterness, and it quickly became a cult favorite in the area.

It was such a hit that, when Schuster’s closed, their customers flocked to nearby Papa’s Tomato Pies, demanding they put mustard on their pizzas. Not wanting to disappoint, Nick Azzaro, the current owner of the 113 year-old restaurant and grandson of the founder, obliged and now Papa’s, already an institution in its own right, has become the de facto home for the mustard pie. In fact, the exterior of their shop is adorned with a sign that proclaims, “Home of the Mustard Pie.”

The Key Steps to True-to-the-Original Homemade Mustard Pizza

I am not new to the mustard pie, and I have spent many nights staring down at an empty Papa’s box with bits of mustard remaining, contemplating this piece of niche pizza history. Deep down, I knew as the food-fixated, pizza-possessed cook that I am that I needed to pay homage with my own recipe. So here we are.

I am not going to give a custom dough recipe here, since I think this wonderful NY Style Pizza Dough recipe plays the role well in a mustard pie. I also tested my recipe with store-bought dough and got similarly awesome results, so you should feel comfortable using whatever is most convenient or appeals to you. I will only say that I do not think a super-thin Neapolitan crust holds up well to the moisture of the mustard and tomato sauce in this pie; I suggest avoiding it here.

Step 1: Pick the Right Mustard

In my research, I found a few local news stories that reported that the mustard used by Papa’s is a brand of spicy brown found in every grocery store. But I wouldn’t be honoring my inner food nerd if I just picked up a bottle of Golden’s and called it a day. I tried six mustards and mustard combinations including straight Dijon, yellow mustard, and a mix of spicy brown and stone-ground to find the one I like best. While each had their merits (I especially loved the pops of the mustard seeds in the stone-ground), I settled on a choice that seems to deviate from the mustard at Papa’s: a combo of Dijon and spicy brown.

Straight spicy brown was great and came the closest to matching the flavor of Pop’s, but I found myself longing for a slightly punchier hit of mustard. After eating far too many slices, I settled on a mixture of equal parts Dijon and spicy brown. The Dijon does not take center stage, but instead makes the spicy brown taste a bit more robust and helps to make the mustard flavor stand out amid the cheese and tomato.

Step 2: Keep the Sauce Simple

My professional pizza-making experience has been exclusively in spots known for their Neapolitan pies. In Naples, the sauce tends to be quite straightforward, not much more than canned tomatoes blended with olive oil and salt. According to the folks at Papa’s, they do the same.

However, I had to do my due diligence. I tested a few pies with a variety of sauces, some barely cooked at all, others simmered for a half hour up to a full hour (in line with this site's NY-Style Sauce). But I found that the more cooked sauces overpowered the mustard with their deeper tomato-paste character. Much better were high-quality canned tomatoes that taste bright and fresh, simply blended and slathered directly onto the pizza. I was still craving a bit of that sweetness typical of many NY/NJ pizzas, so I added a small amount of sugar to bring the sauce more in line with that profile. 

Step 3: Be Selective With Your Mozz

The go-to cheese in most American pizza shops is whole milk, low-moisture mozzarella (I call it WMLM for short). This cheese is different from both fresh mozzarella and also the much more common low-fat, low-moisture mozzarella sold at most supermarkets, but it's the best choice for the cheese on this pie. In contrast to fresh mozzarella’s subtle creaminess, WMLM mozz is comparatively much sharper with a firmness that makes it easy to grate. Fresh mozzarella makes creamy pools of cheese, but what we want is that shiny, cohesive layer of melted cheese you see on most NY-style pies. Low-fat mozzarella, on the other hand, melts into a more rubbery blob that doesn't have the richness of whole milk.

The challenge is that WMLM mozz can be hard to find. If you have trouble tracking it down, whole-milk string cheese is a good alternative, bringing the sharpness and firmness we’re looking for. You could freeze it and grate it or, if you’re not so committed to classic grated cheese shreds, simply slice the string cheese sticks into thin coins.

Step 4: Cook it Right

Cooking spectacular pizza at home without the right setup can be very difficult. Commercial and dedicated home pizza ovens have floors that can reach temps around 800ºF. This ensures that the dough cooks through and browns quickly while the lower ambient temperature melts the cheese a bit slower, ensuring perfect pizza equilibrium. In the lower heat of a home oven, you can easily dry out the cheese and break its emulsion so the fat pools in the time it takes to fully cook the dough below it.

The best luck I’ve had with avoiding this issue in a home oven is by using a thick, high-quality pizza stone or steel and a long preheat time of at least a half hour. These steps, along with cranking your oven to its highest temp, will combine to bring your oven as close as possible to the power of the multi-deck behemoths you see at your local slice shop. Keeping your shredded cheese in the fridge just until ready to bake is also really helpful in balancing out the cheese and dough cooking times.

If, after your first few pies, you’re still ending up with the broken cheese issue, I’d suggest you par-bake your crust for a third of the total time, then, with measured mise at the ready, pull the oven rack out and quickly and carefully add the toppings before sliding the rack back in place to finish. The stone will retain its heat while the reduction in ambient temp from opening the oven will aid you in keeping your cheese from overcooking.

Set oven rack to lower-third position and place a pizza stone or baking steel on it; preheat oven to 500°F (260°C) or as high as your oven will go. Wait at least 30 minutes before baking.

In a food processor, combine tomatoes, olive oil, and sugar and process until mostly smooth with only small chunks remaining. Season to taste with salt. Transfer to a bowl and set aside.

In a small bowl, stir together Dijon and spicy brown mustards and set aside until ready to use. If mixture is too thick, stir in a drop or two of water to loosen slightly for easier spreading.

Set one ball of dough on a well-floured work surface and, using your fingers, press down repeatedly to dock the dough and flatten slightly. Then, using the base of your palm, press the dough into a slightly larger circle roughly 7 inches wide. Next, stretch dough into a 12-inch circle either by draping the dough over your hands and using your knuckles to evenly stretch the dough, or by quickly tossing it back and forth between your hands, rotating the dough to maintain an even circle (this second method is the most effective but also takes the most practice). Lay the dough on a lightly floured pizza peel.

Dollop 1/3 of the mustard mixture onto the center of the dough, then use the back of a spoon to spread the mustard all over the dough, leaving a 1-inch border. Top with 1/3 of the cheese, staying within the border of the mustard.

Using a large spoon, drizzle 2 1/4 ounces (64g), about ⅓ cup, of sauce over the pie. Carefully, but confidently, slide the dough off the peel onto the pizza stone. Cook until the crust is thoroughly browned and the cheese is melted, 12 to 15 minutes.

Using the peel, transfer pizza to a clean work surface and immediately slice. Repeat with the remaining dough balls and topping ingredients.

Notes

If using the linked recipe, prepare it including the instructed 2-hour rest in step 2, then proceed with the dough in this recipe as instructed. If using store-bought dough, each dough ball should be about 9 to 10 ounces (255 to 285 grams); this means that for 3 pizzas you’ll need about 2 pounds of store-bought dough. Most store-bought doughs (both fresh and frozen) are fully proofed, but if not, follow package instructions to prepare for baking.

Special Equipment

Pizza stone or baking steel, pizza peel, food processor

Make-Ahead and Storage

The sauce can be refrigerated in an airtight container for up to 5 days.