Sandwiches aren’t just for lunch anymore. If you own a restaurant, coffee shop or café, you can increase your sales by adding breakfast sandwiches to your menu. The popularity of the breakfast sandwich has surged this year: The product is appearing on 8.1 percent more chain restaurant menus than last year. According to market research firm Technomic, one-third of consumers eat breakfast sandwiches at least once a week. The top ingredients in breakfast sandwiches? Bacon appears in 30.1 percent of sandwiches, followed by ham (23.7 percent) and sausage (22.9 percent). As far as breakfast breads, flatbreads, paninis and croissants are in, while ciabatta bread and tortillas are out.