- 3 cups water
- 1 cup quinoa
- 2 teaspoons olive oil, divided
- 5 skinless, boneless chicken breasts, cubed
- salt and ground black pepper to taste
- 1 yellow onion, chopped
- 1 cup chopped carrots
- 1 cup chopped celery
- 1/2 cup chopped red bell pepper
- 1/2 cup chopped yellow bell pepper
- 2 tablespoons chopped garlic
- 8 cups chicken broth
- 2 cups chopped spinach leaves
- 1/2 teaspoon dried marjoram
- 1/2 teaspoon dried oregano
- 1/2 teaspoon dried basil
- 1/2 teaspoon crushed bay leaf
- 1/3 cup cornstarch
- 1/4 cup cold water
- Bring 3 cups water and quinoa to a boil in a saucepan. Reduce heat to medium-low, cover, and simmer until quinoa is tender, 15 to 20 minutes.
- Heat 1 teaspoon olive oil in a Dutch oven over medium-high heat. Add chicken; season with salt and pepper. Cook and stir until chicken is no longer pink in the center, about 5 minutes. Transfer chicken to a plate.
- Heat remaining 1 teaspoon olive oil in the Dutch oven over medium heat. Add onion, carrots, celery, red bell pepper, yellow bell pepper, and garlic; cook and stir until soft, about 10 minutes.
- Pour chicken broth into the Dutch oven. Add spinach leaves, marjoram, oregano, basil, and bay leaf. Bring to a boil; reduce heat and simmer until flavors combine, about 10 minutes. Stir in cooked quinoa. Return chicken to the Dutch oven; cook until heated through, about 2 minutes.
- Dissolve cornstarch in 1/4 cup cold water in a small bowl. Pour slowly into the Dutch oven; cook, stirring occasionally, until soup thickens, about 1 minute.