Table of Contents
Step 1
Place 2 lb. purple sweet potatoes, peeled, in a large pot and pour in water to cover. Season with kosher salt and bring to a simmer; cook until almost tender, 18–25 minutes. Drain and let sit until dry and cool enough to handle. Slice in half lengthwise and place on a rimmed baking sheet.
Step 2
Meanwhile, toast 1 Tbsp. white sesame seeds in a dry small skillet over medium, stirring occasionally, until deep golden brown, 5–7 minutes. Transfer to a mortar and pestle and let cool. Coarsely crush sesame seeds. (Alternatively, you can smash with the side of a chef’s knife or with a heavy skillet.)
Step 3
Stir together 1 garlic clove, finely grated, ½ cup mayonnaise, 1 Tbsp. finely grated lemon zest, lemon juice, 1 Tbsp. soy sauce, 1 tsp. freshly ground pepper, 1 tsp. sugar, 1 tsp. toasted sesame oil, ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt, and crushed sesame seeds in a small bowl.
Step 4
Prepare a grill for medium-high heat. Drizzle 2 Tbsp. extra-virgin olive oil over sweet potatoes, season with salt, and turn to coat. Grill, cut sides down, until deeply charred underneath, 8–10 minutes.
Step 5
Transfer sweet potatoes to a platter, arranging cut sides up. Using a fork, lightly crush. Spoon dressing over and top with sesame seeds and thinly sliced scallions.
