01 -  Line a 9x13-inch baking pan with parchment paper and lightly grease the surface. 
 02 -  In a large pot, melt the unsalted butter over low heat. Add the mini marshmallows, stirring frequently until fully melted and smooth. 
 03 -  Blend in ground cinnamon, pumpkin pie spice, and vanilla extract until evenly distributed. 
 04 -  Remove the pot from heat. Stir in Rice Krispies cereal, folding quickly to ensure each piece is coated in the marshmallow mixture. 
 05 -  Transfer the mixture into the prepared pan and press evenly using a buttered spatula or wax paper. 
 06 -  In a microwave-safe bowl, melt the white chocolate chips in 20-second intervals, stirring until smooth. Drizzle the melted white chocolate over the top. 
 07 -  Sprinkle dried cranberries, chopped pecans, and festive autumn sprinkles over the surface as desired. 
 08 -  Allow to cool for at least 30 minutes. Cut into 16 squares and serve.