Preheat the oven to 350ºF. Line a large baking sheet with parchment paper.
Spread both cereals onto the baking sheet. Set aside.
In a medium saucepan, melt the butter. Stir in the corn syrup, brown sugar, and salt. Bring to a boil. Once boiling, do not stir and let the mixture cook for 5 minutes.
Remove from the heat and stir in the vanilla and the cinnamon.
Pour the mixture over the cereal on the baking sheet. Pour as evenly as possible. Use a spatula to lightly mix the caramel mixture into the cereal. Try to keep the mixture in as much of a single layer as possible. Do not touch with your hands - it will be very hot.
Bake in the preheated oven for 8 minutes, then remove the baking sheet and stir the mixture again. Return the the oven and bake for an additional 5-8 minutes.
Remove from the oven and stir one more time. Let the mixture sit until cooled, then break into pieces before serving.
