Preheat the oven to 400°F. Line a baking sheet with parchment paper. Evenly place the graham crackers among the baking sheet, creating two rows of 7 graham cracker sheets.
In a saucepan over low heat, add the butter and let it begin to melt.
Add the brown sugar and stir while continuing to heat on low until butter is completely melted and the mixture is combined.
Turn the heat to medium-high until the mixture is boiling and let boil for ~30 seconds. Remove from heat and pour the mixture over the graham crackers. Use a rubber scraper to evenly spread overtop.
Bake for 5 minutes.
Remove from the oven and evenly sprinkle the chocolate chips on top, then the white chocolate chips. Place back in the oven for another two minutes.
Once out of the oven, use a rubber scraper or the bottom of a spoon to spread the chocolate all over the crackers, creating a marble effect.
Sprinkle the nuts, sprinkles, and gems on top.
Allow to cool at room temperature or in the fridge until firm. Break into pieces and enjoy!