Melt the butter. Mix together the flour, oats, brown sugar, baking powder, cream of tartar, and salt.
Make a well in the dry mixture and stir in egg, milk, and melted butter. Stir until blended, then stir in the crystallized ginger chips.
Spoon hand-sized balls of dough on greased cookie sheet and sprinkle the tops with the raw sugar. Bake 10-15 minutes, or until lightly browned. Serve warm. They’re best eaten the day they’re made, but will keep covered for 1 day.