Preheat the oven to 180 °C.
To prepare the filling, place the grated pear, blueberries, sugar, lemon zest and juice into a 23 cm round ovenproof casserole dish. Blend the water and cornflour together in a small bowl, pour over the berry mixture and stir to combine.
To prepare the topping, place the flour, sugar, baking powder and salt together in a food processor and pulse to combine. Add the butter and blend, until the mixture resembles coarse breadcrumbs. Add the cream and blend until it begins to come together. Turn out into a bowl and mix to form a rough, lumpy dough.
Divide the dough into six even pieces. Shape into rough balls and flatten slightly. Arrange five of the balls around the outside of the filling and place one in the centre. Brush the tops with a little cream and sprinkle with demarera sugar.
Bake for 40–45 minutes, until dumplings are golden brown and the filling is bubbling up around the sides.
Allow to cool slightly for 10 minutes, before serving.
Serve with vanilla ice cream or cream.