Grease a 9x13-inch baking dish with butter or line it with parchment paper for easy removal.
In a large saucepan, melt the butter over low heat until it’s fully melted and starts to smell fragrant.
Add the marshmallows to the melted butter and stir constantly with a spatula until completely melted and glossy, about 3-5 minutes.
Remove the saucepan from heat and stir in the vanilla extract, pumpkin spice flavoring, and orange food coloring until evenly combined and the mixture is bright orange.
Pour the rice cereal into the saucepan and gently fold it into the marshmallow mixture until evenly coated and vibrant orange.
Transfer the mixture quickly into the prepared baking dish and press it evenly into a flat layer using a spatula or even your clean hands.
Let the mixture chill at room temperature for 15-20 minutes, allowing it to set and become firm.
Once firm, cut the treats into pumpkin shapes using cookie cutters or a sharp knife and decorate as desired with additional icing or candy if you like.
Arrange the shaped treats on a plate or serve directly for a festive, crunchy Halloween snack.
