Ingredients

2 tablespoons vegetable oil, such as safflower

1 small onion, finely chopped

1/2 yellow or orange bell pepper, chopped

1 celery stalk, finely chopped

Coarse salt and ground pepper

1 pound ground dark-meat chicken

4 hamburger buns

Lettuce, tomato, and mayonnaise, for serving

Preparation

In a large skillet, heat 1 tablespoon oil over medium. Add onion, bell pepper, and celery; season with salt and pepper. Cook, stirring occasionally, until tender, 8 to 10 minutes. Transfer to a medium bowl; cool to room temperature (reserve skillet).

Add chicken to vegetable mixture in bowl; season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Mix to combine. Shape mixture into four 4-inch-wide patties.

In reserved skillet, heat remaining tablespoon oil over medium; cook patties until browned and cooked through, 6 to 8 minutes per side. Place chicken burgers on buns, and top with lettuce, tomato, and mayonnaise.