EatingWell: Elevate your classic burger with 'special sauce'
1 teaspoon distilled white vinegar
1 pound lean (90 percent or leaner) ground beef
2 tablespoons Worcestershire sauce or steak sauce
1/2 teaspoon freshly ground pepper
4 sesame-seed or other hamburger buns, toasted
4 slices 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.
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