1. Heat oven to 425°F (220°C). Line a sheet pan with parchment.
2. In a bowl mix turkey, panko, egg, scallions, garlic, ginger and salt until just combined.
3. Form 16 meatballs and space on one side of the pan.
4. Toss broccolini and pepper with oil and a pinch of salt; spread on the other side. Roast 12 minutes. Meanwhile whisk teriyaki ingredients.
5. Pull pan, brush meatballs with teriyaki and drizzle some over veg; roast 6–8 minutes more until meatballs are cooked through (165°F).
6. Toss meatballs and veg with remaining sauce on the hot pan. Sprinkle with sesame seeds and scallions.