Corti Bros. Market meat department manager Mike Carroll is always on the lookout for something new. So are his customers.

We were with Carroll in the prep area behind the meat counter the other day, watching the master butcher cut steaks from a flat, four-pound roast. This wasn’t just any piece of meat. It was beautifully marbled prime Wagyu beef (American Kobe) from the estimable Snake River Farms of Boise, Idaho.

Specifically, Carroll was cutting the “under-chuck flap” into “zabuton” steaks, so named because of the flap’s shape, similar to that of the flat Japanese sitting cushion. The steaks are also known as “Denver steaks,” a marketing name indicative of nothing.

The flap is from beneath the eye of the chuck, from the steer shoulder, Carroll explained. “The shoulder is the most fatty piece of meat on the steer. For many years, the chuck has just been used for roasts, stews and grinding into hamburger. The bottom flap and the eye of the chuck are tender, but other parts of the chuck are not.

“You won’t find zabuton steaks in many meat departments because most butchers aren’t going to take the time to break down the flap, cut it into steaks and trim them,” he said. You will see them in some restaurants, though, including Japanese “yakiniku” (grilled meats) houses.

What’s the backyard home cook going to do with a zabuton? “Everybody’s looking for something different to grill this summer, and this is it,” Carroll said. “Prep the steaks with a little olive oil and light seasonings, because you want to taste the meat, not the salt. Grill them quickly over high heat, to medium-rare to medium. Or pot-roast a whole flap. I’ve eaten zabuton raw, as carpaccio, and it has a buttery, nutty flavor.”

We tasted a medium-rare zabuton steak and found it remarkably delicious and juicy, and surprisingly tender.

Zabuton steaks in various weights sell for $23 a pound at Corti’s, 5810 Folsom Blvd., Sacramento; (916) 736-3805, www.cortibros.biz.