Melt butter over medium heat in a large pot. Add diced onion and minced garlic, sautéing until translucent (about 5 minutes).

Add peeled and cubed potatoes, stirring to coat them in the mixture. Cook for 3-4 minutes until they are slightly golden.

Pour in the broth, ensuring potatoes are submerged. Bring to a boil, then reduce heat and simmer uncovered for 15-20 minutes until fork-tender.

Remove from heat and use an immersion blender to blend until smooth. For a rustic texture, blend half and mash the remaining potatoes.

Stir in milk or cream on low heat. Season with salt and pepper to taste before serving.

Ladle into bowls and add toppings like cheese, bacon, or scallions as desired.