Sauté your veggies. Heat a large dutch oven or large pot over medium heat. Add butter and let it melt, about 30 seconds. Add onion, carrots, celery, salt, and pepper, and saute for 2-3 minutes until slightly softened. Add garlic and dried thyme, stir to combine, and sauté for another minute.
Make your soup. Add diced potatoes and mix well to combine. Make sure nothing is stuck to the bottom of the pan. Then add the chicken breasts (do not mix them, just layer them on top). Add your broth and make sure everything is covered. Add a little more broth if everything is not covered. Place the lid on the pot and let it simmer, untouched, over medium to medium-low heat for 20 minutes, depending on how thick your chicken is. Be careful that the liquid doesn’t boil over. If needed, adjust the lid so a little air can get in.
Shred chicken. After about 20 minutes, your chicken should be done. Turn down the heat to low and remove from the pan. Let cool for a couple of minutes and shred.
Thicken the soup. Using a measuring cup, remove 1 1/2-2 cups of the cooked potatoes (it’s okay if you get a little carrots and celery) and add to a large measuring cup. Try not to get too much liquid (it’s okay to get some, but less liquid will make it more creamy). Add the cream and a little salt and pepper, and using an immersion blender, blend until smooth and creamy. You can also use a regular blender if you don’t have an immersion blender.
Let simmer. Add shredded chicken back to your pan along with your cream mixture and peas, and mix well to combine. Simmer on low for 2-3 minutes until thickened and warmed through. Stir in lemon juice.
Enjoy!