Preheat your oven to 200°C (400°F) and line a baking sheet with parchment paper for easy cleanup.
Trim off the dark green tops of the leeks, keeping only the white and light green parts. Slice each leek lengthwise into halves or quarters if they are particularly thick.
Rinse the sliced leeks thoroughly under cold water to remove any dirt trapped between the layers, then pat them dry with a kitchen towel.
Place the leeks cut side up on the prepared baking sheet in a single layer. Drizzle generously with olive oil, ensuring each piece is well coated to promote even caramelization.
Sprinkle a generous pinch of salt and some freshly ground black pepper over the leeks. Toss gently with tongs or spatula to coat evenly.
Slide the baking sheet into the oven and roast for about 35-40 minutes. Halfway through, flip the leeks to ensure they caramelize evenly and develop a smoky, golden hue.
Look for leeks that are tender when pierced with a skewer and have edges that are deeply golden and slightly crispy. The aroma should be sweet, smoky, and inviting.
Remove the leeks from the oven and transfer to a serving platter. Squeeze fresh lemon juice over the top to brighten the smoky sweetness.
Let the leeks rest for a couple of minutes to allow flavors to settle. Serve warm or at room temperature, drizzled with any remaining olive oil or additional herbs if desired.
