Burgers with Caramelized Onions

Combine bulgur and 1/4 cup boiling water in a small bowl; let stand until most of the water is absorbed, 20 to 30 minutes.

Meanwhile, heat oil in a nonstick skillet over medium-low heat. Add onions and sugar; cook, stirring occasionally, until the onions are very tender and golden, about 15 minutes. Stir in 2 tablespoons water, vinegar and 1/8 teaspoon salt. Keep warm over very low heat, stirring occasionally.

Preheat the grill or broiler to high. Combine the bulgur, beef, tomato paste, parsley, the remaining 1/8 teaspoon salt and pepper in a medium bowl; knead thoroughly to combine. Shape into two 3/4-inch-thick patties. Grill or broil on a lightly oiled rack until browned and cooked through, about 5 minutes per side. Place the patties on buns, top with the caramelized onions and garnish with lettuce.