Grease the baking pan lightly with butter or non-stick spray to prevent sticking.
In a large saucepan, melt the butter over low heat until it’s just melted and begins to bubble gently, filling the kitchen with a rich buttery aroma.
Add the mini marshmallows to the melted butter and stir continuously until completely melted and smooth, creating a sticky, gooey mixture that crackles softly as it heats.
Remove the pan from heat and stir in the pumpkin puree and pumpkin spice, mixing well until evenly combined. The mixture will turn vibrant orange and smell warm and spicy.
Gradually add the rice cereal to the pumpkin mixture, folding gently with a spatula until all the cereal is coated and the mixture is evenly combined, still sticky but manageable.
Transfer the mixture into the prepared pan and press it down evenly with a spatula or your fingertips coated lightly with butter to ensure it’s compact and smooth on top.
Let the treats cool completely at room temperature for about 15-20 minutes so they set up firmly.
Once cooled, cut into squares or rectangles with a sharp knife for clean edges and serve. Enjoy the gooey, crunchy texture with the warm pumpkin-spice flavor.
