Tender Teriyaki Beef Skewers with Grilled Scallions

Ingredients

• 1 1/2 lb (700 g) flank steak or sirloin, sliced thinly against the grain
• 1 bunch scallions, trimmed and cut into 2-inch pieces
• Wooden or metal skewers
• 1/2 cup low-sodium soy sauce
• 1/4 cup mirin or substitute with sweet rice wine or dry sherry + sugar
• 2 tbsp brown sugar
• 1 tbsp honey
• 1 tbsp rice vinegar
• 1 tbsp sesame oil
• 2 garlic cloves, minced
• 1 tsp fresh ginger, grated
• 1 tsp cornstarch + 2 tsp water for slurry