Heat the olive oil in a Dutch oven over medium-high heat.
Season the chicken breasts with salt and pepper.
Sear the chicken in the hot oil for 3–4 minutes per side, then turn off the heat and remove the chicken.
Add the butter to the pot and allow it to melt, then sauté the onions, carrots, and celery for 3–5 minutes or until tender.
Add the garlic and cook for 1 additional minute.
Add the flour and stir to combine, cooking for 1 minute.
Slowly pour in the chicken broth ¼ cup at a time, stirring continuously and scraping the bottom of the pot, keeping the mixture at a simmer before adding more liquid, until all broth is incorporated.
Stir in the heavy cream, Worcestershire sauce, and bouillon cube, then return the mixture to a gentle simmer.
Add the chicken back to the pot along with the bay leaf, cover, and cook for 30–40 minutes.
Remove the chicken, shred it, and return it to the pot with the baby potatoes.
Continue simmering for about 25 minutes or until the potatoes are tender.
Remove the bay leaf and garnish with parsley if desired.