Bring a large pot of water to a boil, once water is boiling add in potatoes and cook until tender. Strain potatoes from pot and set them aside in a bowl.In a large pot, over medium to high heat add butter, once butter has started to melt add in carrots, cook for 1-2 minutes, then add in onion and celery, season vegetables with 2 teaspoons of Montreal Steak seasoning. Cook until onions are translucent. Add in water and chicken base, bring is a boil. Let it cook over medium heat for 10-15 minutes. In a water bottle or cup with lid add ½ cup of ½ & ½ with the flour, shake vigorously. Add in the remainder of the milk to the pot and then add in flour mixture. Add in frozen peas, potatoes and cubed chicken, season with salt and pepper and add an additional 1-2 teaspoons of Montrell Steak seasoning. Let it simmer 30 minutes, until the soup starts to thicken.Remove from heat and let it sit for 5-10 minutes to cool, then serve.