In a large mixing bowl, cream together butter and sugar until light and fluffy, at least 2-3 minutes. Then add egg, vanilla and molasses one at a time, beating between each addition, making sure everything is well incorporated.
In a separate mixing bowl, whisk together flour, baking soda, cinnamon, ginger, cloves, salt and cardamom.
Add 1/4 of the dry ingredients to the wet ingredients, beating well to fully combine. Continue adding 1/4 of the dry ingredients at a time, beating well after each addition until all is combined. The dough should come together but be fairly sticky to the touch.
Roll or form dough into a log shape and wrap tightly with plastic wrap. Freeze at least 6 hours or overnight.
When ready to bake, preheat oven to 350*.
Unwrap dough log and carefully slice 6 very thin slices (try not to make them any thicker than 1/8") and place on a parchment lined baking sheet.*
Bake for 9-11 minutes until they are a deep brown color and start to look lacey on the top. Remove from the oven and let cool completely on the baking sheet.
Required baking time may vary based on the thickness of your cookies.
*These cookies will spread a lot, which is why it is important that the dough slices have plenty of space and are frozen when they go into the oven - this is what makes them so light and crispy.
I recommend slicing as you go and putting the dough log back in the freezer while each sheet of cookies is baking, rather then slicing the whole log at once. You can control the size of the cookie by the thickness of the dough log and by the size of the slices.