Pre-heat the oven to 180°C.
Put butter, granulated and Muscovado sugar in a large non-stick pan over a gentle heat to make a caramel base.
Peel, quarter and core the pears adding them to the pan as you prepare them and toss them in the caramel to prevent them browning (enzymic).
Allow the pears to soften and go slightly golden, turning from time to time.
Put the flour and 50g of butter in a food processor or rub together for form the texture of breadcrumbs.
Stir in the sugar, oats and almonds.
Add 1 tbsp water and shake to form small lumps.
Stir in the chopped chocolate and crystalised ginger.
Put the caramelised pears into a 1.5lt dish and pour over the crumble topping, spreading it out with a fork, don’t pack it down.
Place in the oven for 40 – 45 minutes.
Serve with cream or ice cream.