Step 1

Bring a few inches of water to a boil in a medium pot fitted with a steamer basket. Halve sweet potatoes crosswise if large and place in steamer. Cover, reduce heat to medium, and steam until fork-tender, 25–30 minutes.

Step 2

Meanwhile, smash together butter, lime juice, tahini, soy sauce, and sesame oil in a small bowl with a fork until smooth, about 3 minutes. Season tahini butter with kosher salt and lots of pepper.

Step 3

Arrange sweet potatoes on a platter or a large plate. Let cool until you can just handle them, then split open and generously spread tahini butter over. Season with sea salt; top liberally with sesame seeds. Serve with lime wedges (this dish really comes alive with lots of bright citrus).