Prepare by lining a 9x9-inch baking dish with parchment paper or greasing it with butter.

Melt the butter in a large saucepan over medium heat, stirring until it bubbles, about 2-3 minutes.

Add jumbo marshmallows to the saucepan and stir continuously for 3-5 minutes until melted and smooth.

Remove from heat and stir in the vanilla extract. Let cool slightly.

Fold in Rice Krispies, Golden Grahams, and mini marshmallows until well-coated.

Transfer half of the mixture into the prepared dish, pressing down to create an even base.

Sprinkle half of the chopped Hershey bars and mini marshmallows over the first layer.

Top with the remaining mixture and press down gently.

Finish with remaining Hershey bars and mini marshmallows on top. Let cool completely, about 30-45 minutes.

Once cooled, cut into squares and serve.