We have two steaks (two carnes asadas) on the Frontera menu—one that we've offered since the day we opened twenty years ago, the other a rather recent addition.

Our original (corn-fed) steak is a boneless rib steak that's marinated in adobo (ancho and guajillo chiles blended with roasted garlic, vinegar and spices), served with black beans, rustic guacamole and fried sweet plantains (that are topped, in a traditional style, with homemade crema and fresh cheese).

Our new carne asada came about after I'd done a lot of research into grass-fed beef and concluded that not having a grass-fed option on the menu was foolhardy. Not only is it one of the healthiest choices you can make at the dinner table (most researchers agree that eating grass-fed beef is as good for you as eating chicken breast), but it's incredibly flavorful--tasting a lot like the pastured beef I remember eating back in Oklahoma as a kid. Sure, the texture is a little more robust than the corn-fed beef most of us are accustomed to, but if you know how to marinate it and cook it, grass-fed can win any dinnertime contest.

First, use a full-flavored marinade to match the full flavor of the meat. I nearly always gravitate to roasted garlic and roasted serrano chiles made into a paste with lime juice and salt, using a food processor.

I spread that thickly on the steak (yes, my favorite steak is a boneless rib steak), let it stand for a few minutes, then spray or brush the steak with oil and grill it over live coals.

The trick with the grilling is to bank the coals to one side so that you have a searing-hot side and a coasting-cool side. Lay the meat on the hot side, let the grill grates sear it darkly before you attempt any moving. Flip the meat over, sear the other side and, if the meat isn't done enough for you, move it to the coasting-cool side to finish slowly.

A note about doneness: I like grass-fed beef cooked one stage less than corn-fed beef. That means for me I'm looking for a rare grass-fed steak or a medium-rare corn-fed steak.

We're proud to say that not only is our grass-fed rib steak outselling our tried-and-true corn-fed rib steak, but we're getting it from Tallgrass Beef, a company started by one of our most loyal customers, Bill Kurtis.

Rick Bayless is an award-winning chef-restaurateur, cookbook author, and television personality. He is the owner of Chicago's Frontera Grill, Topolobampo, and XOCO.