Preheat oven to 350°F and line a large baking sheet with parchment paper.
Cream together the butter and granulated sugar in a large bowl until light and fluffy using an electric mixer.
Add the egg and molasses to the bowl and mix until fully combined.
Gradually mix in the flour, ground ginger, baking soda, and cinnamon until the dough forms evenly.
Divide the dough into six equal portions and roll each into a ball.
Coat each dough ball with extra granulated sugar.
Place the cookies on the prepared baking sheet with space between them, baking in batches if needed.
Bake for 13 to 15 minutes until cookies are set and crackled on top.
Allow cookies to cool on the pan for 10 minutes before transferring to a wire rack to cool completely.
For the frosting, cream together the room temperature butter and cream cheese in a bowl until smooth.
Gradually mix in the powdered sugar until the frosting is fluffy and combined.
Fill a piping bag with the frosting and pipe in a spiral pattern onto the cooled cookies.
Decorate with holiday sprinkles as desired.