Prepare the Potatoes:

Peel and chop the Yukon Gold potatoes into uniform ½-inch cubes. Rinse the cubed potatoes under cold water to remove excess starch, which helps prevent the soup from becoming gummy. Set aside.

Sauté the Aromatics:

In a large pot or Dutch oven, heat the butter (or olive oil and butter combination) over medium heat. Once melted, add the chopped onion and sauté for 5-7 minutes, stirring occasionally, until the onion is softened and translucent, but not browned.

Add the Garlic:

Add the minced garlic and cook for another 1-2 minutes, stirring constantly, until fragrant. Be careful not to burn the garlic, as it can become bitter.

Create the Roux:

Sprinkle the flour over the sautéed onions and garlic. Stir continuously and cook for about 1-2 minutes. This helps cook out the raw flour taste and thickens the soup.

Introduce the Liquids:

Gradually whisk in the chicken or vegetable broth, scraping the bottom of the pot to loosen any flavorful browned bits (fond). Whisk constantly to prevent lumps. Bring the mixture to a simmer.

Cook the Potatoes:

Add the rinsed and drained potato cubes to the pot. Stir well, bring to a gentle simmer, then reduce the heat to medium-low. Cover the pot and cook for 15-20 minutes, or until the potatoes are very tender and can be easily pierced with a fork. Stir occasionally to prevent sticking.

Blend for Creaminess (Partial):

For a creamy texture with some potato chunks remaining, use one of these options:

Immersion Blender: Carefully insert an immersion blender into the pot. Pulse several times until about half to two-thirds of the soup is blended and creamy, leaving some noticeable potato pieces.

Standard Blender: Carefully ladle half of the soup into a standard blender, blend until smooth, then return to the pot with the remaining chunky soup.

Incorporate Dairy and Herbs:

Reduce heat to low. Slowly pour in the whole milk (or half-and-half) and heavy cream (if using), stirring constantly. Add the fresh parsley, chives, and thyme (or dried thyme). Stir to combine and allow the soup to heat through gently for about 5 minutes—don’t let it boil after adding dairy.

Melt the Cheese:

Remove the pot from the heat. Gradually add the shredded sharp cheddar cheese, a handful at a time, stirring continuously until each addition is fully melted and incorporated.

Season to Perfection:

Taste and adjust the seasoning with salt, black pepper, and a pinch of cayenne pepper or smoked paprika (if desired). Be mindful that the cheese adds saltiness, so adjust gradually.

Serve Hot:

Ladle the creamy, cheesy soup into bowls and garnish with your choice of extra cheese, sour cream, fresh chives, or croutons. Serve immediately and enjoy!