Season the chicken thighs generously with salt and black pepper.
Heat the olive oil in a large Dutch oven or other heavy-bottomed pot over medium-high heat.
Once the oil is hot, add the chicken thighs skin side down. Sear for 5-6 minutes or until golden brown, then flip and sear for another 3-4 minutes. Remove the chicken from the pot and set aside on a plate.
Add the onion and garlic to the pot and sauté for 2-3 minutes or until softened.
Add the carrots, celery, and potatoes to the pot and sauté for another 5-6 minutes or until the vegetables start to soften.
Pour in the chicken broth and add the bay leaf, thyme, and rosemary. Stir well and bring the mixture to a simmer.
Return the chicken to the pot, skin side up. Cover and simmer for 30-35 minutes or until the chicken is cooked through and the vegetables are tender.
Add the frozen peas to the pot and stir well. Cook for another 2-3 minutes or until the peas are heated through.
Remove the bay leaf from the pot and discard. Serve hot, garnished with chopped fresh parsley.