Boil the lentils in 800ml water for 15 mins
until almost tender. Meanwhile, fry the
onions and chillies in the 50g butter for
about 7 mins until starting to soften. Stir in
the ginger, garlic and spices and cook over
a low heat for 1 min more.
Pour in 800ml boiling water followed by
the cooked lentils and any liquid. Add the
bay leaves and beans, then simmer for
20 mins more until thickened. This can be
made 2 days ahead and chilled, or frozen
for up to 1 month.
To serve, return to the heat if necessary
and stir in the cream. Season well. Pour into
a bowl, dot with the remaining butter, dust
with garam masala and scatter with coriander.