Heat 2 tablespoons of olive oil or butter in a large pot over medium heat. Add the sliced large yellow onion and sauté for 8–10 minutes until they become soft, fragrant, and golden brown.

Stir in 2 minced garlic cloves and cook for an additional minute until aromatic. Add in 4 peeled and diced medium Yukon Gold or Russet potatoes, stirring to coat them well.

Pour in 4 cups of vegetable or chicken broth and bring to a boil. Once boiling, reduce the heat to low, cover, and let it simmer for 15–20 minutes until the potatoes are fork-tender.

Using an immersion blender, blend the soup until reaching your desired consistency. Blend until smooth for a creamy texture or mash some potatoes for a chunkier soup.

Stir in 1/2 cup of whole milk or heavy cream if desired, season with salt and pepper, and simmer for another 2–3 minutes.

Ladle the soup into bowls and garnish with fresh thyme or chives. Serve alongside crusty bread or croutons.