Melt 2 tablespoons of butter in a large pot over medium heat. Add diced onion and cook 5 minutes until translucent. Stir in garlic and cook 1 minute, careful not to burn.

Add diced potatoes and 4 cups broth. Bring to a boil, then reduce heat and simmer 15–20 minutes until potatoes are fork-tender.

Mash potatoes lightly for a rustic texture, or use an immersion blender for a smooth consistency.

Stir in 1 cup heavy cream and 1 cup shredded cheddar until melted and creamy. Add thyme, salt, and pepper to taste.

Ladle into bowls, garnish with herbs or extra cheese, and serve hot with crusty bread.