Preheat the oven to 200°c/gas mark 6 and grease an 22-cm square ovenproof dish with butter.
Drain the pears and arrange them on the base of the prepared dish. Put all the remaining ingredients in a processor and blitz until you have a batter with a soft dropping consistency.
Spread the brown batter over the pears, and bake in the oven for 30 minutes. Let stand for 5 or 10 minutes and then cut into slabs - I cut 2 down and 2 across to make nine slices - and serve with chocolate sauce.