Grilled directly over the coals (a gas grill works well, too), the thickest part of the steak was medium‑rare (125 degrees) in 10 minutes. After letting the meat rest, I thinly sliced it against the grain. The chipotle paste was a keeper, but the thinner areas of the steak were overdone. What’s more, the meat was unevenly browned and didn’t have much grill flavor.
For my second try, I sliced the steak into thirds lengthwise. This separated the tapered edges from the thicker center so I could grill each piece to the proper doneness. These narrow strips, once sliced, would also fit nicely into 6-inch tortillas.
The mediocre browning in my first test had been a result of the steak buckling as it cooked; the bottom of the steak (closest to the heat source) cooked more quickly than the top, which caused its fibers to shrink and gave the meat a concave shape. Frequent flipping helped the top and bottom shrink at about the same rate, so the steak stayed flat and browned evenly.