Prepare an 8x8 dish with a thin coating of cooking spray or oil. Also grease the back of a metal spoon. Set aside.
Mix spices and salt in a small bowl and set aside.
In a medium/large pot, melt butter over medium/medium low heat. Allow the butter to simmer until it browns and exudes a nutty aroma. With a metal spoon, stir to release the browned bits from the bottom and side of the pan as they form. Do not overbrown/burn the butter.
While continuing to cook on medium low heat, pour in mini marshmallows. Stir continuously with a metal spoon, scraping the bottom of the pot with each stir.
Once the marshmallows are mostly melted (you'll still see some marshmallow outlines and shapes, but mostly the mixture will be melted), remove from heat. Overcooking can lead to hard treats instead of chewy, so don't worry about a few marshmallow outlines in the mixture. They'll smooth out in the next step.
Immediately pour cereal over the marshmallow mixture and sprinkle with spice mix. Stir to combine and then pour into the prepared dish.
Smooth the top of the treats with the greased back of a metal spoon.
Let the mix rest for at least an hour before slicing.
Dust with additional cinnamon and slice.