Heat 1/2 tbsp oil for spice paste in a pan and fry red chillies till fragrant.Cool and grind to a smooth paste with remaining ingredients for spice paste.
Cut duck into 5-cm pieces,wash well and pat dry.
Mix spice paste into duck and marinate for 2 hours.
Place duck in a pressure cooker with scant 1 cup water and cook umder pressure for 15 minutes.
Strain and reserve stock.
Heat oil in a pan,add duck and saute till brown,Remove from pan and set aside.
Add onions and potatoes to pan and fry till onions turn translucent.Remove onions and potatoes from pan and set aside.
Reduce oil to 2 tbsp,add shallots and fry till brown.
Sprinkle in flour,mix well and add duck and reserved onions,potatoes and stock.Mix well,bring to boil and simmer till potatoes are tender and gravy thickens.