Pumpkin Spice Chex Mix

So, after a bit of mad experimentation, I've invented a new Chex Mix recipe.
Here's how to make a half batch:
1.  Mix 1.5 cups each of Corn Chex, Rice Chex, and Wheat Chex, 1 cup of pretzel sticks, and 1 cup of walnuts in a large, microwave-safe bowl.
2.  Mix half a stick of butter, 1 teaspoon each of cinnamon, ginger, nutmeg, and allspice, and 1.5 teaspoons of brown sugar in a normal-sized, microwave-safe bowl.
3.  Microwave until the butter is completely melted, stirring every 10 to 15 seconds.
4.  Mix the sauce into the dry ingredients.  This part can be challenging, especially as the spices want to settle to the bottom of the bowl.  The best way that I've found is to take the stirring tool that was used for the sauce and get a bit onto it, scraping the bottom to get the spices, and then stir that into the dry mix.  This method is slower, but has the added benefit of allowing you to get sauce on every piece.
5.  Microwave for about 4 minutes (but use your judgement, based on your microwave - ours is pretty intense), stirring every minute in the first (roughly) half, and every 30 seconds in the second (roughly) half.  Mostly, just get the center moved to the outside and the bottom moved to the top, to even out heating and prevent burning.
6.  Spread the result out onto aluminum foil to cool.
That's it, really.  The spices essentially emulate pumpkin pie spice, and the brown sugar helps to bring out the taste.  I was going for an autumn taste, and I think that I got it.