But black people were at the root of many southern culinary traditions. Those traditions have traveled with African-American families who resettled throughout the country. “Black hands were in that pot all the time, and still are,” said Omar Tate, the chef and founder of Honeysuckle, a pop-up dinner series in New York and Philadelphia that uses food to explore black identity.

Popeyes would not provide information about its customer demographics. But over all, African-Americans, who are about 13 percent of the country’s population, buy more fried chicken than their numbers would indicate: nearly 30 percent of all fast-food fried chicken, and 15 percent of all breaded chicken sandwiches, according to the NPD Group, a market research firm.

Ms. Ali, who wrote the Facebook post comparing the Popeyes sandwich to Chick-fil-A’s, said she wasn’t suggesting that white people could not cook as well as African-Americans — just differently. They seem to rely on precise measurements, she said.

“Black folks don’t cook like that,” she said. “Our recipes are a little bit of this, a little bit of that. We season until it’s right. That’s what Popeyes tastes like.”

Mr. Tate, the chef, said it was difficult to liken Popeyes to authentically black cooking. When he thinks of authenticity, he thinks of the techniques of someone like Edna Lewis, a pioneering black chef, who fried meats in lard and seasoned the fryer with smoked pork.

“That’s authentic. That’s what soul food is to me,” he said. “It’s one of those black magic things that can’t be reproduced.”

Popeyes’ inroads with black Americans may be as much about marketing as anything else. The company has made appeals to African-Americans in its advertising, stoking criticism that it is pandering. When the chain introduced a fictitious black woman named Annie the Chicken Queen in its commercials about a decade ago, some people criticized it as racist. Ms. Alvarez, the Popeyes spokeswoman, declined to discuss the company’s marketing.