Preheat oven to 350f degrees. Spray a donut pan with nonstick cooking spray. In a large bowl, stir together flour, baking soda, both sugars, cinnamon and ginger. Beat in butter, egg, milk, and molasses until evenly blended.
Spoon batter into a zip top bag, and cut off one bottom corner. Pipe batter into each donut mold, up to level with the pan.
Bake for 15-20 minutes, then set aside to cool.
Once donuts are cooled, whisk together milk, powdered sugar, in a wide bowl. Take a cooled donut and dip one side into the prepared frosting, then lift up and place on a cooling rack. Add sprinkles.
Notes
When making the frosting, you want it stiff instead of runny, so keep adding powdered sugar until it is the right texture.
Also, when dipping your donuts, wiggle them around a little to get the frosting spread completely. Lift up quickly.