01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving a slight overhang for easy removal.
02 - In a medium bowl, whisk together flour, ground ginger, cinnamon, nutmeg, cloves, baking soda, and salt until well blended.
03 - In a large mixing bowl, cream unsalted butter, brown sugar, and granulated sugar together until light and creamy. Beat in molasses, egg, and vanilla extract until fully integrated.
04 - Gradually add dry ingredients to wet mixture, mixing just until incorporated. Avoid overmixing.
05 - Evenly spread batter into prepared pan. Bake for 18 to 20 minutes, until surface is set but center remains slightly soft.
06 - Remove pan from oven. Immediately sprinkle mini marshmallows, assorted candies, and white chocolate chips over warm surface. Return to oven and bake an additional 3 to 5 minutes, until marshmallows puff and candies begin to melt.
07 - Allow bars to cool completely in the pan before lifting out using parchment overhang. Slice into 16 bars once fully cooled.