Using a stand mixer fitted with the paddle attachment or hand-held mixer, cream the butter and brown sugar until fluffy and lighter in color. Add the molasses and yolks and beat until smooth.
While things are creaming away, mix all your dry ingredients together. Add dry ingredients, candied ginger and zest of your orange the creamed mixture and mix until just combined.
Roll your dough into a log about 3” thick. Wrap in parchment or plastic wrap and chill for at least one hour.
Heat oven to 350F and line two baking sheets with parchment paper. Brush the log of cookie dough with egg whites. Place the sprinkles on a tray or flat plate. Roll the log into the sprinkles. Slice 1” thick pieces and place on cookie sheets. Bake for 7-8 minutes, or until just setting on the outside edges. Cool completely before removing them from the pans.