Make the Cookies!
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Whisk together flour, baking soda, ginger, cinnamon, clove, nutmeg, cream of tartar and salt until combined and set aside.

Add vinegar to milk and set aside to sour until needed.

Using an electric mixer, combine shortening, white sugar and molasses on medium for about 3 minutes. Add egg yolks and vanilla extract, beating on medium for about 1 minute or until combined, remembering to scrape down sides as you go.

Mix in 2-3 batches, alternate between adding dry ingredients or soured milk into wet ingredients on low speed. Cover with plastic wrap, and refrigerate for an hour.

Preheat oven to 350°F and line baking sheets with parchment paper (or aluminum foil can work in a pinch). Roll 1 Tbsp cookie dough into balls, place on baking sheet with 2" spacing, and bake for 11-12 minutes.

Transfer cookies to wire rack to cool.

Make the Frosting!
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Combine marshmallows, sugar, water and vinegar in a glass or metal bowl over a pot of simmering water, steaming the bowl until the marshmallows melt, stirring occasionally.

Remove the bowl from heat and - beating with an electric mixer on medium - add egg whites. Beat for 7-10 minutes, until fluffy, adding vanilla extract at the end.

Sift confectioners' sugar into the marshmallow mixture and stir until blended.

For the "signature look", hold the now-cooled cookies upside down between two fingers and dip into the frosting until the top surface (facing down) is sufficiently covered.

Alternatively, you can spread the frosting over your cookies with a spatula or knife.

Let cookies sit out until frosting has cooled and hardened (do not refrigerate until frosting is firm).

Eat!