Preheat oven to 350 degrees Fahrenheit. Line an 8x8" pan with parchment paper so it hangs over the edges.

In the bowl of an electric mixer, cream together butter, sugar, egg, and molasses. In a separate bowl, stir together baking soda, salt cinnamon, cloves, ginger and flour. Add it to the wet mixture and mix until combined.

Spread/press dough into parchment paper-lined pan and bake for approximately 25 minutes. Allow them to cool completely.

To make the drizzle, stir together powdered sugar and milk (adding more milk a little at a time, if needed, until it reaches the desired consistency). Drizzle the bars, let it set, then slice and serve.