Preheat oven to 350F. Line a 9” round cake pan with foil and spray with cooking spray.
Cream butter and sugar in the bowl of an electric mixer fitted with the paddle attachment. Add molasses and mix until mixture is smooth. Add eggs and vanilla and beat until combined. Mix in baking soda, ginger, cinnamon, nutmeg, cloves, and flour.
Press mixture into prepared pan. Bake 19-22 minutes until the top just begins to get golden and is no longer shiny. I like my cookie cake more on the raw side, so I cook it on the shorter side. If you like it more done, let it cook longer. Let the cookie cool completely, then remove from pan and remove foil. Place on serving plate.
Whisk powdered sugar, vanilla, and milk in a small bowl. Transfer to a Ziploc sandwich bag and snip off one tip. Decorate cookie in desired pattern, top with sprinkles. Let set before serving.
Gift suggestion: Bake the cookie in a new 9” cake pan, without the foil. Let it cool in the pan, then frost it in the pan. Wrap it with cellophane and give it as a gift!