Combine the maraschino cherries and the chocolate vodka in a small jar and cover. Refrigerate overnight, shaking a few times.
Preheat heat oven to 350 degrees. Grease a 5 inch cast iron skillet with butter or cooking spray. Set aside.
In a medium mixing bowl, cream together the butter and sugars until light and fluffy. Add in the egg and vanilla extract and mix well. Now add in the flour, cocoa, baking soda, and salt and mix until just combined.
Drain the vodka soaked cherries, and add them to the cookie batter. (Reserve a few of the cherries to top the cookie with, if desired.) Add in the dark chocolate chips and fold both the cherries and the chocolate chips into the cookie batter.
Spread the cookie batter evenly into the prepared skillet. Bake for 20-25 minutes or until the edges are done. The center should still look slightly under baked (don't worry- it isn't!).
Let the cookie cool to warm. While the cookie is cooling, prepare the glaze. In a small mixing bowl, whisk together the powdered sugar, corn syrup, water, and cherry juice until smooth.
Garnish the top of the cookie with the reserved cherries and then drizzle with the glaze.