Step 1: Sear the Chicken (Optional, but Recommended)

1. Pat the chicken thighs dry with paper towels and season generously with salt and pepper.

2. Heat the olive oil in a large skillet over medium-high heat.

3. Carefully place the chicken in the hot skillet and sear for 3-4 minutes per side, until golden brown. You are not cooking the chicken through, just creating a flavorful crust.

4. Transfer the seared chicken to the bottom of your slow cooker (6-quart or larger). Do not wipe out the skillet.

Step 2: Sauté the Aromatics

1. Add the chopped onion, carrots, and celery to the same skillet you used for the chicken. Sauté over medium heat for 5-7 minutes, until the vegetables begin to soften.

2. Add the minced garlic and cook for another minute until fragrant, stirring constantly to prevent burning.

3. Pour about 1/2 cup of the chicken broth into the skillet to deglaze the pan, scraping up all the flavorful browned bits from the bottom with a wooden spoon. This step captures all the delicious flavor from searing.

4. Pour the vegetable and broth mixture from the skillet into the slow cooker over the chicken.

Step 3: Slow Cook

1. Add the rinsed pearl barley, the remaining chicken broth, dried thyme, dried rosemary, and bay leaves to the slow cooker.

2. Stir everything gently to combine.

3. Secure the lid on the slow cooker. Cook on LOW for 6-8 hours or on HIGH for 4-5 hours. The soup is ready when the chicken is cooked through and tender, and the barley is soft and chewy.

Step 4: Shred the Chicken and Finish the Soup

1. Carefully remove the cooked chicken from the slow cooker and place it on a cutting board.

2. Using two forks, shred the chicken into bite-sized pieces.

3. Remove and discard the bay leaves from the soup.

4. Return the shredded chicken to the slow cooker.

5. Stir in the frozen peas. They will cook in about 5 minutes from the residual heat.

6. Taste the soup and season with additional salt and pepper as needed. The final seasoning is crucial for a perfectly balanced flavor.

Step 5: Serve

1. Ladle the hot soup into bowls.

2. Garnish generously with fresh chopped parsley and serve immediately.