In a large pot over medium heat, melt two tablespoons of butter until foamy. Add one medium diced onion and sauté for about 5 minutes, or until it becomes translucent. Next, stir in three minced garlic cloves and cook for an additional minute.

Incorporate diced potatoes into the pot along with four cups of chicken or vegetable broth. Increase the heat to bring the mixture to a rolling boil. Then reduce the heat to low and let the soup simmer for 15-20 minutes, or until the potatoes are fork-tender.

Partially mash the potatoes using a potato masher right in the pot, or for a smoother consistency, carefully blend the mixture with an immersion blender.

Lower the heat and add one cup of heavy cream alongside one cup of shredded sharp cheddar cheese. Stir continuously until the cheese has melted and the mixture is fully combined.

Season your soup with dried thyme, salt, and pepper to taste. Ladle the warm soup into bowls.