Let's whip up this comforting soup! Start by prepping the leeks—wash them and slice them diagonally, using only the whites and light greens.
Heat a large pot or Dutch oven over medium heat, then add the butter (or olive oil).
Once the butter is melted and sizzling, toss in the sliced leeks and sauté them for about 5 minutes.
Next, add in the onion, garlic, and seasonings (kosher salt, black pepper, and thyme), and sauté everything together for another 4-5 minutes until fragrant.
Once the onions are soft, add in the potatoes, broth, and cream (or milk), and give it all a good stir.
Bring the soup to a gentle boil, then cover the pot, reduce the heat to low, and let it simmer for 20 minutes until the potatoes are fork-tender.
Now, remove the soup from the heat and use an immersion blender to blend it until smooth, keeping a bit of texture for that homemade feel—don't over-blend!
Once the soup is just right, ladle it into bowls and garnish with chopped chives, a drizzle of olive oil or cream, and a sprinkle of sea salt and black pepper. Then, dive in and savor every spoonful!