Preheat your oven to 375°F. Trim the root ends off the leeks, split each lengthwise, and slice the white and light green parts into 1/4-inch rounds. Submerge the slices in a bowl of cold water, agitating gently to dislodge any sand or grit. Transfer the cleaned leeks to a colander; a few damp strands are fine. Meanwhile, peel the potatoes and reserve the peels in cold water to prevent discoloration. Slice the potato flesh into 1/4-inch rounds.

In a medium pot over medium-high heat, melt the butter. Add the drained leeks, minced garlic, 1 teaspoon kosher salt, and a generous grind of black pepper. Sauté gently, stirring occasionally, until the leeks become tender and translucent (about 7 to 10 minutes).

Pour in the broth along with the sliced potatoes and add a bay leaf. Bring the mixture to a simmer, then reduce the heat to medium-low, cover, and let it cook for roughly 15 minutes or until the potatoes yield easily to a spoon’s pressure.

While the soup is simmering, pat the reserved potato skins dry and spread them in a single layer on a parchment-lined baking sheet. Drizzle lightly with olive oil, sprinkle with salt, and toss to coat evenly. Roast in the oven for 10-15 minutes, checking around 10 minutes until your desired crispiness is achieved. Once crisp, set aside for garnish.

Discard the bay leaf. Using an immersion blender (or transfer half the soup to a countertop blender for a partial puree), blend the soup until it reaches your preferred texture. Taste and adjust the seasoning with extra salt and black pepper as needed.

Spoon the soup into bowls, add a squeeze of fresh lemon juice, and swirl in a generous dollop of sour cream. Sprinkle chopped chives over the top and add a scattering of the crispy potato skins. Serve immediately.