CHICAGO — Pepperoni may be the perennial favorite, but such pizza toppings as eggs, kale and butternut squash are on the rise. While consumers remain true to traditional varieties, restaurants are rolling out more premium pie flavors. Take Pizza Hut, for example, which in November added Peruvian cherry peppers, sriracha sauce and a curry crust to the menu.

“Chains primarily, but independents as well, are looking to innovate to capture more folks than the just cheese, pepperoni, sausage folks,” said Jennifer Aranas, project manager at Datassential, a Chicago-based food industry research firm. “People know that’s available, so how do you grab the younger demographics, that millennial age group that tends to be more daring when trying new things?”

In its latest report on the pizza category, Datassential tracked menu trends and surveyed consumers on pizza consumption and purchasing patterns. Two out of three Americans eat pizza every week, with 40% of respondents picking pepperoni on their most recent slice, followed by sausage and meat lovers (both 16%), supreme (15%), cheese (8%) and vegetarian (7%).

While the classic varieties are most widely available in restaurants, such toppings as cotto salami, pepper bacon and pancetta are among the fastest growing proteins on pizza.

“When we look at sauces and flavorings, what we see out there already are marinara, barbecue, pesto, but some of the highly trending flavors are garlic cream, truffle oil, balsamic glaze,” Ms. Aranas said. “Some of toppings that we’re seeing growing faster than traditional toppings are kale, shallots, sage, a lot of fall vegetables like butternut squash, roasted mushrooms.

“In terms of cheese, there are more premium cheeses out there like taleggio, burrata, actual Parmesan reggiano. Leaning toward that more upscale type of cheese.”

Pizza Hut recently added such toppings as sriracha sauce and Peruvian cherry peppers to the menu.

Nearly half of consumers said the crust is the most important component of a pizza, and 30% are interested in wood-fired or coal-fired styles.

“This might indicate that consumers are really leaning toward that more authentic style or understanding that cooking method and technique affect the quality of their pizza,” Ms. Aranas said. “They’re a little more educated in not just that it’s a style but a cooking method that has to be high heat with a certain kind of Italian flour that you just can’t get from any other type of pizza.”

The base can make or break a pie for many consumers, who reported dissatisfaction with the quality of crust from take-and-bake and frozen pizzas.

“Some of their top frustrations are that the crust is cardboardy or not what they get when they order pizza from a restaurant,” Ms. Aranas said. “From a barrier standpoint from what retail offers, that is one of their top things because when consumers are making it at home, they oftentimes can’t get to the temperature they need it to be to get a really good crust or they’re cooking it in their microwave.”

Consumers said generous toppings, more innovative varieties and discounts would drive more retail pizza purchases. On the food service side, coupons and convenient ordering are top incentives.

“Papa John's, Domino's and Pizza Hut are all using technology to facilitate easy pizza ordering and keep it top of mind,” Ms. Aranas said. “They’ve done things like integrating pizza ordering into gaming systems and apps.”

Flatbreads bubbling up

Also delivering strong growth in the category are flatbreads, which are moving the dish into new day parts. Bonefish Grill, for example, offers on its dessert menu a brioche flatbread with berry sangria preserves, mascarpone cheese, candied pecans and creamy wine custard sauce.

Flatbreads appear on the dessert menu at Bonefish Grill.

“For over half of our consumer panel, pizza centers around dinnertime, and there was about a third who are consuming pizzas at lunch,” Ms. Aranas said. “What’s nice with flatbreads is you can serve them at those two meal parts, but then it not just crosses meal part lines; it also crosses menu lines.

“It can be an appetizer, you can use it for late night as a nosh, it can be bar food, it can be upscale lounge food. So I think it has a little more versatility over pizza.”

Flatbreads also are 10 times more likely to feature gourmet ingredients, such as beef tenderloin, Havarti cheese and tomato aioli, according to the report.

“What’s interesting with flatbreads that is not so much the case with pizza is that they index higher with unique or upscale ingredients,” Ms. Aranas said. “For places that offer pizza, and they can’t really step out of customer’s comfort zone with pepperoni and sausage and cheese, flatbreads allow them get out of those traditional offerings by being able to offer it in upscale way, and their customers aren’t necessarily griping about ‘Oh, my favorite pepperoni pizza’s not here anymore, all because you replaced it with pork belly.’

“You can still have that pepperoni pizza and that flatbread as an additional offering instead of one that can potentially cannibalize existing offerings.”

While gluten-free crusts and truffle oil may be trending, Ms. Aranas noted the pizza category isn’t changing fundamentally.

“When we surveyed our consumer panel, the vast majority, over 60%, are focused on traditional flavors,” she said. “They still want their favorite comfort flavors. So, I think when chains are innovating, they’re not just trying to do well with those flavors but to keep it top of mind.

“There are so many choices, and I think that’s part of the innovation, just keeping this thing that’s been out there in ubiquity for a long time and keep it at the forefront at people’s minds when they’re thinking of somewhere to eat.”