Remove the roots, outer leaves, and tops from the leeks. Thinly slice the white and light green parts of the leek. Rinse in a bowl of cold water and then drain.
Heat oil in a large saucepan over medium heat. Add the leeks, onions and garlic. Mix them around in the oil and then lower the heat to medium-low. Partially cover, and cook for 15 minutes, stirring occasionally.
Add the broth and potatoes to the pot and bring to a boil over medium-high heat. Cover, reduce heat, and simmer until the potatoes are soft (about 10 minutes).
Make a purée with an immersion blender until the soup is smooth. Season with salt and pepper, to taste.
Serve with the frizzled leeks.
For the Frizzled Leeks
Remove the roots, outer leaves, and top from the leek. Cut it in half lengthwise and then into slices. Rinse them in a bowl of water to remove any dirt. Drain and pat dry.
In a small non-stick frying pan, heat the canola oil over medium-high heat. Add the leeks to the oil. Fry the leeks, stirring constantly, until the leeks are golden brown (about 5 to 7 minutes).
Remove the frizzled leaks to a bowl with paper towel to remove excess oil. Use them as a topping for the soup.
Notes
Yukon Gold potatoes have a thin skin and so peeling them is optional.
For the frizzled leeks, instead of slicing them width-wise, you can also choose to slice them into 3" long strips.
For a thicker soup, you can use a couple more potatoes.
The soup makes for great leftovers and reheats on the stove well. The soup can be stored in the fridge in an airtight container for up to 5 days. It can also be stored in the freezer for up to 6 months, but make sure it cools down first.
Looking for a vegetarian or vegan option? This recipe can be easily modified with a vegetable based broth.
If it's too thick after you've puréed it, simply add some more broth until it's the right consistency for you and let it reheat.
Potatoes, if over-mashed or over-blended, release their starches and this results in a sticky, gluey texture. Blend until they are just so smooth, then stop to avoid a gloopy mess.