King Trumpet Yakitori

• 1 scallion, thinly sliced
• ⅓ cup mirin
• ⅓ cup sake
• ⅓ cup soy sauce
• ⅓ cup zarame sugar or raw sugar
• 4 small king trumpet mushrooms, trimmed, halved lengthwise, cut crosswise into 2-inch pieces
• 1 teaspoon vegetable oil

Kosher salt

• Eight 6-inch bamboo skewers, soaked at least 15 minutes

1. Soak scallion in ice water until crisp, at least 10 minutes. Drain.
2. Meanwhile, bring mirin, sake, soy sauce, and zarame sugar to a boil in a small saucepan; reduce heat and simmer until slightly reduced, 12–15 minutes. Set tare aside.
3. Prepare grill for medium heat. Thread 3 mushroom pieces onto each skewer. Brush lightly with oil and season lightly with salt. Grill until golden brown, about 1 minute per side. Then cook, brushing with tare and turning occasionally, until glazed and tender, about 2 minutes more. Serve mushrooms topped with scallions.
4. Do Ahead: Tare can be made 3 days ahead. Let cool; cover and chill. Reheat before using.