Peel and dice the potatoes into ½-inch cubes. Finely dice the onion, carrots, and celery. Mince the garlic cloves.

In a large Dutch oven, melt 2 tablespoons of butter over medium heat. Add the diced onions, carrots, and celery. Sauté for 5-7 minutes until softened.

Add the minced garlic, dried thyme, and rosemary. Cook for another 30 seconds until fragrant.

Add the diced potatoes to the pot and stir to combine with the aromatic vegetables.

Pour in the chicken broth. Bring to a boil, then reduce heat to maintain a gentle simmer. Cover and cook for 15-20 minutes until potatoes are fork-tender.

While the potatoes simmer, melt the remaining 2 tablespoons of butter in a small saucepan over medium heat. Add the flour and whisk continuously for 1-2 minutes to cook out the raw flour taste.

Slowly whisk in the milk and heavy cream into the roux until smooth. Continue cooking for 2-3 minutes until slightly thickened.

Pour the cream mixture into the potato soup pot, stirring gently to incorporate.

For a chunkier soup, use a potato masher to partially mash some of the potatoes. For a smoother creamy texture, use an immersion blender.

Stir in salt, pepper, and nutmeg. Add half the shredded cheese and stir until melted. Taste and adjust seasoning if needed.

Ladle the soup into bowls. Top with crumbled bacon, remaining cheese, fresh chives, and a dollop of sour cream.