Cut the boneless skinless chicken thighs into bite-sized pieces and season with salt and pepper.

In a large pot, melt the butter over medium heat. Add the diced onion, sliced carrots, and celery, cooking until softened for about 5-7 minutes.

Add the minced garlic and cook for another minute until fragrant.

Increase the heat to medium-high and add the chopped chicken. Cook until browned on all sides, around 5-6 minutes.

Sprinkle flour over the chicken and vegetables, stirring constantly for about a minute.

Slowly add the chicken broth while stirring to combine. Bring to a gentle boil, then reduce to a simmer.

Stir in cubed yellow potatoes, dried thyme, salt, and black pepper. Cover and simmer for 15-20 minutes or until potatoes are tender.

Once potatoes are cooked, stir in whole milk and heavy cream. Let it heat through and adjust seasoning to taste.

Ladle soup into bowls and top with shredded sharp cheddar cheese and fresh chives.