2 tablespoons canned chipotle chiles in adobo, including sauce
1 lb ground beef chuck
1/2 cup finely chopped onion
1 teaspoon salt
4 English muffins or hamburger buns, halved horizontally

Prepare grill for cooking over medium-hot charcoal (moderate heat for gas); see "Grilling Procedure," below.
Meanwhile, open any whole chipotles and discard seeds, then mince chipotles.

Mix chipotles (with sauce), beef, onion, and salt with your hands,
then form mixture into 4 (3/4-inch-thick) patties.

Grill burgers on lightly oiled grill rack, covered only if using gas grill,
turning over once, 4 minutes total for medium-rare.
Grill English muffins, cut sides down, until grill marks appear, about 30 seconds.
Serve burgers in English muffins.

Cooks' note:
If you aren't able to grill outdoors, burgers can be cooked in a hot well-seasoned
ridged grill pan over moderately high heat, turning over once, about 7 minutes total for medium-rare.

Grilling Procedure
If using a charcoal grill, open vents on bottom of grill, then light charcoal.
When charcoal turns grayish white (about 15 minutes from lighting),
hold your hand 5 inches above grill rack to determine heat for charcoal as follows:
Hot: When you can hold your hand there for 1 to 2 seconds
Medium-hot: 3 to 4 seconds
Low: 5 to 6 seconds
If using a gas grill, preheat burners on high, covered, 10 minutes, then, if necessary,
reduce to heat specified in recipe.

Makes 4 servings.