Gather all your ingredients and tools including a large pot or Dutch oven, a cutting board, sharp knife, measuring cups and spoons, and a potato masher or immersion blender.

Wash and peel the russet potatoes, then cut them into roughly 1-inch cubes.

Melt the butter in the pot over medium heat. Add the diced onion and cook for about 5 minutes until softened and translucent.

Stir in the minced garlic and cook for an additional minute.

Sprinkle the flour over the sautéed onions and garlic and stir well. Cook for around 2 minutes.

Slowly pour in the chicken or vegetable broth while stirring constantly to avoid lumps. Add the diced potatoes, bring to a boil, then reduce to a simmer. Cook for about 15-20 minutes until the potatoes are fork-tender.

Use an immersion blender to puree the soup to your desired consistency, or carefully transfer batches to a regular blender.

Return the mixture to the pot if using a regular blender and stir in the milk or heavy cream. Heat through on low, but do not boil.

Season with salt and pepper as needed and add any optional herbs.

Ladle the soup into bowls and serve with toppings.

Enjoy the soup hot, topped with shredded cheese, crispy bacon bits, fresh chives, or sour cream.