Sear Chicken (Optional): Heat a large skillet over medium-high heat and add a drizzle of olive oil. Season the chicken thighs with salt and pepper, then place them in the hot skillet, searing for 2–3 minutes on each side until golden brown. Transfer the seared chicken to the slow cooker.

Prepare Vegetables: In the same skillet, reduce heat to medium and add a bit more olive oil if needed. Sauté chopped onions, celery, and carrots for 3-4 minutes until they soften and become fragrant, then stir in minced garlic for about 1 minute.

Combine Ingredients: Transfer the sautéed vegetable mixture to the slow cooker. Add chopped potatoes, chicken broth, tomato paste, thyme, rosemary, and bay leaf. Stir everything well to combine.

Cook Stew: Cover the slow cooker with its lid and set it to cook on LOW for 7 hours or HIGH for 4 hours.

Finish Stew: In the last 15 minutes of cooking, stir in peas. For a thicker consistency, mix flour with water to create a slurry and stir it into the stew.

Serve: Remove the bay leaf and ladle the warm Chicken Stew into bowls. Garnish with freshly chopped parsley.