Slice the potatoes to about a ¼" thickness and set aside.
In a large bowl combine the butter, sugars, cardamom, cinnamon, bourbon or maple syrup, vanilla, and mix thoroughly. Toss the potatoes to coat evenly and then pour the potatoes into the 9 x 13 inch baking dish.
Cover and bake for 1 hour. Remove the foil, gently rotate the potatoes every 20 minutes replacing the foil before putting back into the oven.
Allow to cool uncovered for 10 minutes before serving.