Preheat the oven to 375°F.Drop the butter into a 9×13 inch baking dish (or similar size oval dish) and place in the oven to melt, 10 minutes.Stir together the 1 cup + 2 tablespoons flour, baking powder, ginger, cinnamon, and salt. Add the milk, brown sugar, molasses, and vanilla, and mix until combined.In a bowl, toss the blueberries with 1/4 cup brown sugar and 2 tablespoons flour. Pour the batter over the melted butter. Spoon the blueberries over the batter. Bake 50-55 minutes, until the center is just set and the edges begin to brown. Serve warm with ice cream or whipped cream. Enjoy!!