Heat oven to 350 degree F. Pour melted butter into 8 or 9 inch square baking dish.
In medium bowl, whisk together Bisquick mix, sugar, and milk; pour over melted butter.
Sprinkle blueberries evenly over Bisquick batter. Bake 42 to 47 minutes, or until golden brown. Serve warm.
We have found and often do substitute other items instead of blueberries. This has been done with, pears, plums, apricots, peaches, cherries, as well as frozen bagged fruits. Tonight we plan to try it with rhubarb.