In a large pot, heat olive oil over medium heat. Add the diced onion and minced garlic, sautéing until the onion is translucent, about 5 minutes.

Add the cubed chicken to the pot, cooking until browned on all sides, approximately 7-10 minutes.

Stir in the chicken broth, potatoes, carrots, celery, thyme, salt, and black pepper. Bring to a simmer.

Reduce heat to low, cover, and let it cook for 25 minutes, or until the vegetables are tender.

Once the vegetables are tender, stir in the heavy cream and the cornstarch mixture. Cook for an additional 5 minutes, stirring constantly until the sauce thickens.

Finally, add the frozen peas and stir until heated through, about 2 minutes.

Serve hot, garnished with fresh herbs if desired.