1 medium onion, chopped
1 tablespoon(s) canola oil
2 tablespoon(s) ketchup, divided
2 tablespoon(s) low-fat mayonnaise
2 teaspoon(s) dill pickle relish
1 teaspoon(s) distilled white vinegar
1 pound(s) lean (90-percent or leaner) ground beef
2 tablespoon(s) Worcestershire sauce or steak sauce
1/2 teaspoon(s) freshly ground pepper
4 sesame-seed or other hamburger buns, toasted
4 slice(s) tomato
4 leaves green-leaf lettuce
Preheat grill to medium-high (or see Stovetop Variation).
Combine onion, oil, and 1 tablespoon ketchup in a medium saucepan. Cover and cook over medium-high heat, stirring often, until the onion is softened, 5 to 7 minutes. Reduce heat to medium-low, uncover and cook, stirring occasionally, until very soft, 5 to 8 minutes more. Transfer to a medium bowl and let cool for a few minutes.
Meanwhile, combine the remaining 1 tablespoon ketchup, mayonnaise, relish, and vinegar in a small bowl. Set aside.
Add beef, Worcestershire (or steak sauce), and pepper to the onion and gently combine without overmixing. Form into 4 patties, about 3/4 inch thick.
Oil the grill rack (see Tip). Grill the burgers, turning once, until an instant-read thermometer inserted in the center registers 165 degrees F, 4 to 5 minutes per side.
Assemble the burgers on toasted buns with the ketchup-mayonnaise sauce, tomato slices, and lettuce.
courtesy of delish.com