For the Sponge:
Whip egg whites until stiff. Gradually whisk in sugar.
Stir in yolks. Fold in cocoa.
Spread onto a greased tray in a 1/4" thick layer.
Bake at 180 degrees C until firm to the touch. Cool.
To Prepare the Pears:
Peel the fruit.
Dissolve sugar in water with remaining poaching ingredients.
Boil for five minutes. Add pears to the pan.
Cover and poach until tender. Cool.
For the Sauce:
Melt sugar in a heavy pan.
Gradually pour in warmed cream.
Dissolve over a gentle flame.
Add butter in small pieces. Set aside.
Arrange pears on sponge.
Pour on the sauce.
Decorate with cream and mint sprigs before serving.