The St. Louis rib offers the best of two ribs: the lush marbling of baby backs and the meaty richness of spareribs. Picture a center-cut section of a rack of spareribs trimmed down to the approximate shape and size of a rack of baby backs. It’s easy to cook, tender to the tooth, with flavor that just doesn’t quit. That’s why the St. Louis cut is our go-to rib at Barbecue University. And few prepare it better than Chris Conger of the Smoke Shack in San Antonio, Texas.
Step 1: To cook the ribs the way Chris does, use the tip of a paring knife to make a lengthwise slit in the membrane on the back (hollow, or concave, side) of each rack midway between the top and bottom of the ribs.
Step 2: Make the rub: Combine the brown sugar, paprika, garlic powder, salt, pepper, onion powder, chile powder, and cumin in a mixing bowl and mix well. If using conventional brown sugar, break up any lumps with your fingers.
Step 3: Place the ribs on a rimmed baking sheet and sprinkle both sides of them with the rub, rubbing it into the meat. Use enough rub to coat the ribs (1½ to 2 tablespoons on each side of each rack); store any excess in a sealed jar away from heat or light. It will keep for several weeks.
Step 4: Cover the ribs with plastic wrap and cure overnight in the refrigerator. The overnight cure is optional, but it gives you a richer flavor.
Step 5: Set up your smoker following the manufacturer’s instructions and preheat to 225° to 250°F. Add the wood as specified by the manufacturer.
Step 6: Place the ribs directly on the rack in the smoker, rounded (convex) side up. Smoke the ribs until they’re very tender and the meat has shrunk back from the end of the bones by ¼ to ½ inch. When you lift a whole rack with tongs, it will bend like a bow and start to break. And you should be able to pull the individual ribs apart with your fingers. Total cooking time will be 3½ to 4 hours.
Step 7: Meanwhile, make the glaze: Melt the butter in a saucepan over medium heat. Stir in the brown sugar, honey, vanilla, and 3 tablespoons water. Bring to a boil, stirring well, until the sugar has melted and the ingredients are well combined, 5 minutes. The glaze should be thick but pourable; add additional water if needed. Brush the ribs all over with the glaze 5 minutes before the end of cooking.
Step 8: Transfer the ribs to a cutting board. Pry up the membrane on the back of each rack with the probe of an instant-read thermometer and pull it off, grabbing it with a dish cloth or paper towel. Brush the racks on both sides with the glaze a second time. You can serve the racks whole, cut in half, or as individual bones. Serve any remaining glaze on the side.
For maximum flavor, rub the ribs the night before so they have time to cure in the refrigerator before smoking. Pressed for time? You’ll still get good flavor if you smoke the ribs immediately after applying the rub. Note the unusual membrane technique here: Conger slits the membrane but leaves it on to keep in moisture. He removes it just before glazing and serving.