Tsukune (Japanese Chicken Meatballs)

Tare Sauce:--
½ cup mirin
½ cup soy sauce
¼ cup saké
¼ cup dark brown sugar
1 tbsp sherry vinegar
3 cloves of garlic, smashed & peeled
3 spring onions, roughly chopped
3 cm piece of ginger, sliced
1 tbsp whole black or white peppercorns
Meatballs:--
800 g ground chicken thighs
½ cup bread crumbs
¼ cup finely chopped spring onions
1 large egg, lightly beaten
½ tsp SIDS CRAZY SALT
2 tsp finely grated fresh ginger
2 tsp finely minced fresh garlic
1 tsp toasted sesame oil
2 tsp SIDS SALT & PEPPER
8-10 soaked wooden skewers

Tare Sauce: Combine all the ingredients in a medium saucepan. Bring to boil over high heat, then reduce to a simmer, whisk to combine and cook until mixture is thick and syrupy, about 45 minutes. Strain through a fine mesh strainer. Set aside or store in an airtight container in the refrigerator until ready to use.
Meatballs: Using hands, mix together chicken, bread crumbs, spring onions, egg, SIDS CRAZY SALT, ginger, garlic, sesame oil, SIDS SALT & PEPPER until thoroughly combined. Form mixture into 2 cm meatballs and thread onto skewers.
Clean and oil the grilling grate. Careful transfer skewers to grill, if necessary supporting meatballs from bottom to prevent them from falling off skewers. Grill until first side is well browned, about 3-4 minutes. Using tongs, rotate meatballs and cook until well browned on second side, about 2-3 minutes. Repeat for remaining two sides.
Brush tare sauce all over meatballs and allow to cook for 15-30 seconds longer. Transfer skewers to a plate or serving dish, brush lightly with sauce again and let rest for 5 minutes. Serve immediately.