Cut ribs into single bone portions and place them in a large pot and cover with cold water.

Bring to simmer and skin off froth. Reduce the heat, cover and continue to simmer until tender, about 20 minutes; drain and set aside.

In a bowl, combine the hoisin sauce, vinegar, honey, garlic, ginger, Chinese 5 spice and hot pepper flakes – mix well to incorporate the spices.

Preheat your oven to 425°F.

Arrange the ribs on a foil-lined rimmed baking sheet; brush with half of the sauce. Roast in oven at 425°F for 5-10 minutes (depending on how meaty your ribs are). Turn the ribs over and brush them with the remaining sauce; continue to roast until browned and the sauce starts to caramelize, cook for another 5-10 minutes.

Sprinkle with sesame seeds and green onions.