Ingredients

1 teaspoon vegetable oil, plus more for brushing 

1 red onion, sliced into 1/2-inch-thick rings 

Coarse salt 

3 tablespoons lime juice 

1 1/4 pounds lean ground turkey 

4 whole-wheat hamburger buns, split 

1 ripe Hass avocado 

1 cup shredded romaine lettuce 

1/3 cup jarred pickled jalapenos, drained and cut into strips 

1/4 cup fresh cilantro 

Preparation

Heat oil in large nonstick skillet over medium heat. Cook onion with 1/4 teaspoon salt, covered, stirring occasionally, until tender, about 7 minutes. Transfer to a bowl, and toss with 2 tablespoons lime juice.

Heat grill to medium-high. Divide turkey into 4 equal pieces. Shape each into a 3 1/2-inch patty (about 3/4 inch thick). Brush both sides of burgers with oil, and season with 3/4 teaspoon salt. Grill until cooked through and an instant-read thermometer inserted into centers reaches 155 degrees, about 4 1/2 minutes per side (3 1/2 minutes if using a grill pan). Grill buns, cut sides down.

Meanwhile, mash avocado with a fork, and mix with remaining tablespoon lime juice and 1/4 teaspoon salt. Spread onto buns. Sandwich romaine, burgers, onion, jalapenos, and cilantro between buns.