Here is how "we" made it.
Gluten-free Frito Snack Mix
3 cups Frito's
3 cups Rice Chex
3 cups Glutino Pretzels
2 cups mixed nuts (in the version picture we just used cashews due to a severe peanut allergy)
1 cup brown sugar (packed)
1/2 cup butter
1/2 cup lite corn syrup (or brown rice syrup)
2 cups M&Ms
Mix the Frito's, nuts, Rice Chex, and Pretzels and spread on a pan ("we" spread on two pans). In a small sauce pan, combine the sugar, butter, and corn syrup and cook over medium heat, stirring for four minutes.
Preheat oven to 350 degrees. Pour evenly over the Frito's mixture and bake 8-10 minutes. Remove from oven and turn mixture over before returning to the oven to bake another 8-10 minutes (I actually did help with this step!). If using two pans, be sure to switch the one on top to the bottom.
Spread the mix out on tin foil to cool. Once completely cool, break apart and transfer to a large bowl. Mix in M&Ms. Enjoy!
UPDATE: If you would rather use brown rice syrup (mentioned above), be careful not to overcook! As a matter of fact, shorten the baking time by several minutes, and check it regularly to make sure it is not getting too brown!