Line a 9 x 13 pan with parchment and spray with non-stick spray.
Mix sugar, ginger, cinnamon and salt, then cream in lard. Mix in egg yolks and molasses.
In a separate dish, dissolve baking soda in hot water. Add to first mix.
Mix in flour. Dough should be dense but spreadable.
Spread in prepared pan. Bake at 350 F until toothpick inserted off center comes out clean, about 20 minutes.
After taking the gingerbread out of the oven, prepare the frosting.
In a free-standing mixer or large metal mixing bowl, beat egg whites until stiff. Do not over beat.
In a small saucepan, mix sugar and water. Heat on medium, stirring just until sugar dissolves. Once mixture comes to a boil be sure not to stir or it will crystalize. Heat to 238 - 242 F (soft ball stage).
When sugar is up to temperature pour into egg whites, beating until mixture is fluffy but still spreadable. Immediately spread over (partially cooled) gingerbread. I let the frosting cool and harden on the bars at room temperature, but you could serve when it's cool, even if still soft.
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.