Preheat the oven to 350 and grease a deep dish pie plate, 9″ square or round baking dish.
Combine the pears, lemon juice, cinnamon, ginger, flour and salt in a mixing bowl. Toss well. Add the frozen blueberries and toss again. Set aside and prepare the batter.
In a small mixing bowl, lightly whisk the flour, sugar, baking powder, salt. Add the butter, egg, vanilla and milk and whisk until a batter forms.
Pour the pears and blueberries mixture into the greased baking dish. Add a few small dollops of butter atop the pears.
Pour the batter over the top, spreading lightly. It will spread as it cooks.
Bake at 350 for 40-50 minutes, or until batter has cooked through and begins to turn golden on top.
Serve warm with ice cream, whipped cream or as is.