Bring the water, sugar, vanilla and lemon zest to the boil in a large pan while stirring. Add the tea bags, leave to steep for approx. 5 mins., remove. Add the pears, cover and simmer for approx. 15 mins. until soft. Carefully remove the pears, drain.
Mix the flour, baking powder, sugar, salt and cinnamon in a bowl. Add the butter and rub together using your hands to form an even, crumbly mixture. Add the buttermilk, mix quickly to form a soft dough – do not knead. Arrange the pears in the prepared dish. Place the cobbler mixture next to the pears in the dish, top with the hazelnuts.
Approx. 30 mins. in the centre of an oven preheated to 180°C.
Remove from the oven, dust with icing sugar.