Dice your onion, carrots, and celery into roughly equal sizes to ensure even cooking.

Heat a large stockpot over medium heat and add the butter. Once melted and foaming, add the diced onion, carrots, and celery. Stir occasionally and sauté for about 5 minutes until the onion becomes translucent and the vegetables start to soften.

Pour the chicken broth into the pot and add the whole chicken breasts. Bring the mixture to a gentle boil, then reduce heat to maintain a low simmer.

Simmer for 12 to 15 minutes until the chicken reaches an internal temperature of 165°F (74°C). The meat should be opaque and easy to shred with a fork.

Remove the chicken breasts to a cutting board and let them cool for a few minutes. Then shred into bite-sized pieces using two forks or your hands.

Return the shredded chicken to the simmering broth.

Stir in the cubed potatoes, dried thyme, and dried sage. Bring the soup back to a simmer and cook for about 15 minutes until the potatoes are just becoming tender but still hold their shape.

Add the drained butter beans and frozen corn to the pot. Stir gently to combine and simmer for another 5 minutes until heated through.

Pour in the heavy cream and stir to combine.

In a small bowl, whisk together the cornstarch and cold water until smooth. Slowly add this slurry into the soup while stirring constantly to avoid lumps.

Simmer for 2 more minutes until the soup thickens.

Taste the soup and season with salt and black pepper gradually to your preference.