In a saucepan on medium heat, combine your mini marshmallows and butter. Melt and continue to stir until fully combined.
After about 6 minutes, or until the marshmallows are almost completely melted, add the pumpkin puree and the pumpkin spice seasoning.
Mix until fully combined, over the heat. Once combined, remove and pour the mixture over the cereal in the prepared bowl.
Stir and fold until all the cereal pieces are covered.
Press into a lightly greased 9 x 13 inch pan.
Let them cool for about 20 minutes then slice and serve.
Garnish with cinnamon if desired.
Notes
This recipe is a lot like any other Rice Krispy Treat recipe, but it's important that you add the correct ingredients at the right time, for the best results. If you don't, your treats will come out a little bit strange of a texture.