Select SEAR/SAUTÉ Mode. Press Temp/Time button to set the time to 15 minutes with the knob. Press START.
When the cooking vessel is hot, add olive oil and butter.
Place chicken pieces in the vessel by spreading on the bottom as much as possible. Let it sit for around 4 minutes to brown and then stir occasionally until chicken is browned enough.
Add onions and garlic and sauté until fragrant, for about 2 minutes.
Press CANCEL.
Select MANUAL 2. Press Temp/Time button and set the temperature to 325°F and set the time to 30 minutes. Press START.
Stir in carrots, potatoes, and celery. Sauté until carrots are partially soft for around 4 minutes.
Pour in flour and stir for 2 minutes to cook the flour.
Add peas, Italian seasoning, thyme, salt, black pepper, and chicken stock. Scrub any bits stuck to the bottom of the vessel.
Add milk and stir well.
Close the lid.
Cut puff pastry into the shape you prefer. Bake in the hot oven according to the instructions.
When the program ends, open the lid carefully and season with salt and pepper to taste.
Serve the soup and garnish with chopped parsley. Add baked puff pastry on top of the soup bowls.