Buffalo Burgers With Pickled Onions

DIRECTIONS:Make sauce: Roast bell pepper on rack of a gas burner over highheat, turning with tongs, until skin is blackened, 12 to 15 minutes. (Or broilpepper on a broiler pan about 5 inches from heat, turning occasionally, about 15minutes.) Transfer to a bowl and cover tightly, then let stand 20 minutes.When cool enough to handle, peel pepper, discarding stem and seeds, and coarselychop. Purée pepper in a blender with dressing, garlic, paprika, and salt untilsmooth, then transfer to a bowl and chill, covered, until ready to serve.Grill onions: Peel onions and trim root ends slightly, leaving onionswhole, then halve lengthwise and cut halves lengthwise into 1/2-inch-thickwedges. Insert 1 wooden pick through each wedge to hold layers together whilegrilling, then put onions in a bowl. Heat vinegar, sugar, and salt in asmall nonreactive heavy saucepan over moderate heat, stirring, until sugar isdissolved. Pour pickling liquid over onions, stirring occasionally to coat withliquid, and let stand 5 minutes (onions will brighten in color), then drainonions and pat dry. Prepare grill for cooking. If using a charcoal grill,open vents on bottom of grill, then light charcoal. Charcoal fire is medium-hotwhen you can hold your hand 5 inches above rack for 3 to 4 seconds. If using agas grill, preheat burners on high, covered, 10 minutes, then reduce heat tomoderate. Grill onions on a lightly oiled grill rack, covered only if using agas grill, turning over once, until tender, about 5 minutes total. Remove anddiscard wooden picks. Grill burgers: Sprinkle salt and pepper on bothsides of burgers, then grill burgers on lightly oiled grill rack, covered onlyif using a gas grill, turning over once with a spatula, 5 to 6 minutes total formedium-rare. Meanwhile, grill English muffins, turning over once with tongs,until toasted, about 3 minutes total. Serve burgers on muffins topped with sauceand onions. Cooks' note:If you aren't able to grill outdoors, you can usea hot well-seasoned ridged grill pan. Grill onions first, then burgers, thenmuffins, all over moderately high heat. (Burgers may take 1 minute longer thanif cooked outdoors.) Lower heat during cooking as necessary. Available atspecialty foods shops and Tienda.com.**Available at Whole Foods stores.Makes 4 servings. Each serving contains about 250 calories and 14 gramsfat. Recipe By: Epicurious.com