For the filling add peaches, berries, brown sugar, lemon juice, arrowroot and cinnamon to a bowl. Mix gently and let sit while you prepare the batter.
In a large bowl, whisk together the flour, brown sugar, baking powder, salt and lemon zest. Add the butter and cut in with a pastry blender until crumbly. Pour in boiling water and stir until combined.
Pour fruit into a dish and spoon batter mixture over the fruit, gently spread.
For the topping mix the cinnamon and sugar and sprinkle over the batter.
Bake at 375 for 45-55 minutes
Allow to cool and serve with ice cream or whipped cream.