Make the Broth: Heat 1 tsp sesame oil in a saucepan. Gently sweat smashed garlic and ginger slices for 2-3 mins. Add chicken broth, the white parts of the scallions, and 1 tbsp soy sauce. Simmer gently, covered, for at least 20 minutes.

Prep the Glaze: While broth simmers, pat chicken dry. In a small bowl, whisk 1/4 cup soy sauce, brown sugar, mirin, and 1 tsp sesame oil. It will be thick and viscous.

Sear the Chicken: Heat 1 tbsp vegetable oil in a large skillet over medium-high heat. Sear chicken pieces for 3-4 minutes per side, until browned. Work in batches if needed.

Caramelise (Get Gooey): Turn heat to medium. Pour the thick, gooey glaze mixture over the chicken. Toss constantly as it bubbles. The glaze will reduce and become extremely thick and sticky, coating the chicken. This takes 2-3 minutes. Remove from heat immediately.

Assemble: Strain the aromatics from the broth. Ladle the hot broth into bowls.

Serve: Place the sticky, caramelised chicken pieces in the center of the broth. Garnish with the sliced green scallion tops and sesame seeds.