Add the light brown sugar, fresh ginger, ground cinnamon, ground ginger, nutmeg, ground cardamom, and salt. Pour in the melted unsalted butter and mix until combined. Pour in the half and half and stir until well integrated. Finally, add a 1/4 cup of bourbon and stir once again.
½ cup light brown sugar, 1 tsp fresh ginger, 1 tsp ground cinnamon, ½ tsp ground ginger, ½ tsp ground nutmeg, ½ tsp ground cardamom, ½ tsp kosher salt, 2 tbsp unsalted butter, 1½ cups half and half, ¼ cup bourbon