1.Peel, core and halve the pears; cut each half into 6 wedges. Add pear, butter and caster sugar to a large frying pan, covered, over medium heat. Cook for 5 minutes, stirring occasionally, until the pear is just softened.
2.Meanwhile, preheat oven to moderate, 180°C (160°C fan-forced). Grease and line a deep 22cm round cake pan with baking paper. Arrange pear slices in base of pan.
3.Beat the remaining ingredients, except the chocolate, in a large bowl with an electric mixer on slow speed until combined. Beat a further 2 minutes on medium speed. Beat in chocolate until combined.
4.Pour mixture over pears in prepared pan. Bake in a moderate oven for about 1 hour 15 minutes or until cooked when tested. Stand for 10 minutes before turning onto a wire rack to cool.
Pears will ripen more quickly if you store them at room temperature in a paper bag with an apple.Note