Peel the carrots and two of the shallots and chop into big chunks
Place the mackerel fillets, carrots and shallots in a saucepan
Add the wine and the thyme, then cover the ingredients with water
Bring to the boil, remove from the heat and poach the fish for 15 minutes
Allow to cool
Drain the fish and remove the skin from the fish and any bones
Finely dice the remaining shallot and carefully cut the tarragon leaves
Place the fish in a bowl and add the mustard and sour cream
Mix well
Add the tarragon, shallot, curry powder and chilli powder
Season with salt and freshly ground black pepper
Cool in the fridge
Serve with fresh country bread and a wedge of lemon
This mixture will keep for upto 4 days.