Sesame-Braised Leeks

Trim roots and dark green tops from leeks, leaving 5 to 8 inches of white and light green parts. Cut the leeks in half lengthwise. Keeping the layers intact, rinse well, taking care to remove any grit; pat dry. Whisk broth, brown sugar and fish sauce in a small bowl and place next to the stove.

Heat sesame oil in a medium skillet over medium heat. Add leeks to the pan, cut-side down, and cook, without turning, until starting to brown, 2 to 5 minutes. Pour the broth mixture around the leeks and bring to a simmer. Reduce heat to maintain a lively simmer and cook until the leeks are very soft and the liquid has completely evaporated, 20 to 30 minutes.

Remove the pan from the heat and transfer the leeks to a serving platter, cut-side up. Add butter to the pan and scrape up any browned bits. Pour the sauce over the leeks. Garnish with sesame seeds, if desired.