In a large pot on medium-high heat, warm olive oil.
Add onion, carrots, celery and garlic and cook for 5-6 minutes until tender. Add thyme, nutmeg, salt and pepper and cook for an additional 1 minute until fragrant.
Reduce heat to a medium, add butter and warm until completely melted. Add flour and whisk into melted butter and vegetable mixture until completely incorporated.
Add broth, stirring to combine and scraping up any sticky bits from the bottom of the pot.
Add chopped potatoes and bay leaf, stir, cover and allow to simmer for 20 minutes on low heat or until they can be pierced with a fork.
Once cooked, add milk and cream, stirring to combine. Add shredded chicken and frozen peas and mix until well incorporated in the soup.
Continue to cook for an additional 10 minutes until everything has heated through. Season with additional salt, pepper and parsley (optional) to taste.
This soup can be served immediately, stored in an airtight container in the fridge for up to 5 days or in the freezer for 3 months.