Dry-fry peppercorns, cumin, and coriander seeds for 5 minutes then grind.
Blend ground spices with chilli, shallots, garlic, ginger, lemongrass, lime leaves, cinnamon, turmeric, fish sauce, oil, and sugar.
Score duck skin and cook skin-side down in a cold pan over medium heat for 5 minutes.
Turn duck to brown the other side and remove from pan to keep warm.
Cook one tablespoon of curry paste in the duck fat until fragrant.
Add 250ml stock and 400ml coconut milk to the pan and bring to a boil.
Slice the duck breasts thinly and add them to the liquid to simmer for 3 minutes.
Add spring onions, red pepper, and aubergines and cook for 5 minutes until soft.
Serve curry over rice and garnish with coriander and lime wedges.