How to Make It
In a small saucepan, combine the soy sauce, mirin, crushed garlic cloves, sliced ginger and sugar. Cook over moderate heat until slightly reduced, about 5 minutes.
Meanwhile, in a food processor, pulse the mushrooms until minced; transfer to a bowl. Pulse the chicken until very finely chopped; add to the bowl. Add the miso, 2 tablespoons of oil, the scallions, minced garlic and ginger, salt and pepper to the chicken and mushrooms and mix well.
In a small nonstick skillet, cook one-third of the chicken mixture over moderate heat, stirring, just until the meat is no longer pink, 2 minutes. Let cool slightly, then mix the cooked chicken back into the raw mixture until blended.
Form the meat into twelve 1/4-cup oval patties, about 3/4 inch thick. Thread two meatballs and 2 shishito peppers onto each of 6 skewers. Transfer the skewers to a baking sheet and refrigerate for at least 15 minutes.
Light a grill or preheat a grill pan; oil the grate. Brush the meatballs and peppers with oil and grill, turning once and basting with the sauce, until lightly charred and cooked through, 4 minutes per side. Serve warm.
Shishito peppers are available at farmer’s markets.