I start by cooking the wild rice blend according to its package directions. While it’s halfway done, I move on to the next step so everything finishes around the same time.
In a large pot, I melt 1 Tbsp butter over medium heat, then add the chopped onion, carrots and celery and sauté for about 4 minutes. I toss in the minced garlic and sauté for another 30 seconds. Then I add the chicken broth, herbs (thyme, marjoram, sage, rosemary), season with salt and pepper, add the chicken breasts, bring to a simmer, cover and reduce to medium-low heat. I cook until the chicken is done (about 12-16 minutes), rotating thicker pieces midway.
Once the chicken is cooked, I remove it, let it rest 5 minutes, then shred into bite-size pieces. Meanwhile, in a separate saucepan, I melt the remaining 6 Tbsp butter, stir in the flour and cook for about 1½ minutes while whisking. Then I add the milk slowly while whisking, stir in the heavy cream, cook until thickened.
Finally, I add the thickened milk mixture into the large pot with the broth, shredded chicken, cooked rice and lemon zest, stir it all together, and remove from heat. I let the soup rest just a bit before serving so the flavors meld.