Preheat your oven to 200°C (390°F). Line a baking sheet with parchment paper to keep things tidy.
Trim the dark green tops from the leeks, leaving only the white and tender pale green parts. Slice each leek in half lengthwise to reveal the layers and make even roasting easier.
Gently rinse the sliced leeks under cold water to remove any dirt lodged between the layers. Pat them dry thoroughly with a kitchen towel to ensure they roast without steaming.
Arrange the leek halves cut side up on the prepared baking sheet. Drizzle generously with about 3 tablespoons of olive oil, making sure each piece is well coated and glistening.
Sprinkle the leeks with sea salt and freshly cracked black pepper. Tuck optional sprigs of thyme or rosemary among them for added aroma.
Place the baking sheet in the oven and roast for about 35-40 minutes. Check at the 20-minute mark and rotate the pan to promote even caramelization. The leeks should turn a deep golden brown and become tender when pierced with a fork.
Once done, remove the leeks from the oven and let them rest for a few minutes. They will be soft, smoky, and beautifully caramelized at the edges.
Squeeze fresh lemon juice over the roasted leeks to brighten their smoky sweetness. Give them a gentle toss or serve as is for a stunning presentation.
Transfer the leeks to a serving dish and enjoy warm, their rich, tender texture complemented by the fresh citrus zing.
