Preheat the oven to 160 celsius (320 Fahrenheit) and line the base and sides of a 23cm springform cake tin with baking paper.
Place the butter and sugar in the bowl of an electric mixer and beat until pale and creamy. Switch the mixer to low and gradually add the beaten eggs followed by the ground almonds, flour and cardamom. Mix until combined.
Place half the cake mixture into the prepared tin and cover with half the pear and chopped chocolate. Cover with the remaining cake mixture and place in the oven for 20 minutes. Carefully remove the cake and push the remaining pieces of chocolate into the top of the cake and top with the remaining pear in whatever pattern you prefer. Sprinkle the pear with caster sugar and return to the oven to bake for a further 40 minutes, or until the cake is cooked and the centre of the cake springs back when lightly touched. Remove the cake from the tin and cool for at least 20 minutes before serving. Serve at room temperature or slightly warm with a dollop of cream.