Active Time

　　30 min

　　Total Time

　　40 min

　　Barbecue sauce from the bottle pales beside the 15-minute stovetop version here. We've paired it with a tender flatiron steak that may just become your favorite new cut of beef.

　　

Ingredients

Makes 4 servings

　　3 tablespoons packed dark brown sugar

　　2 teaspoons ground cumin

　　2 teaspoons chili powder

　　1 1/2 teaspoons salt

　　1 teaspoon black pepper

　　1 teaspoon dry mustard

　　1 (1 1/4 -pound) flatiron steak (1 inch thick; also called boneless chuck top blade steak)

　　1 medium onion, finely chopped

　　1 tablespoon vegetable oil

　　1/2 cup ketchup

　　2 tablespoons Worcestershire sauce

　　5 tablespoons water

　　

Step 1

Stir together brown sugar, cumin, chili powder, salt, pepper, and mustard in a bowl. Pat steak dry and rub all over with 2 tablespoons spice mixture. Reserve remainder for sauce. Marinate steak at room temperature while making sauce.

　　

Step 2

Cook onion in oil in a 1- to 1 1/2-quart heavy saucepan over moderately high heat, stirring, until golden brown, 5 to 10 minutes. Stir in ketchup, Worcestershire sauce, and reserved spice mixture and bring to a boil over moderately high heat, stirring occasionally. Reduce heat and cover, then simmer until onions are very tender, about 5 minutes. Transfer to a blender and purée with water (use caution with hot liquids) until very smooth (add additional water, 1 tablespoon at a time, if necessary), then transfer to a bowl.

　　

Step 3

Meanwhile, preheat gas grill burners on high, covered, 10 minutes, then reduce heat to moderately high.

　　

Step 4

Oil grill rack, then grill steak, covered, 4 to 5 minutes per side for medium-rare. Brush steak all over with some of sauce and grill 30 seconds per side.

　　

Step 5

Transfer to a cutting board and let stand 5 minutes. Cut steak into thin slices and serve with remaining sauce.