Preheat & Prep: Preheat your oven to 350°F (175°C). Line a large, rimmed baking sheet with high-quality parchment paper.

Combine Cereal: In a large mixing bowl, toss together the Rice Chex and Rice Krispies cereals. Set aside.

Start Caramel: In a medium, heavy-bottomed saucepan, melt the butter over medium heat.

Add Flavorings: Once the butter is melted, stir in the brown sugar, vanilla extract, cinnamon, and salt. Stir gently until the sugar begins to dissolve.

Boil: Bring the mixture to a steady, rolling boil while stirring continuously. Cook for exactly 2 to 3 minutes until the caramel noticeably thickens and lightens slightly in color.

Coat Cereal: Remove from heat immediately and pour the hot caramel over the cereal mixture. Gently toss with a silicone spatula until the cereal is evenly and completely coated.

Bake: Spread the coated mixture into an even layer on the prepared baking sheet. Bake in the preheated oven for 7 to 9 minutes.

Cool: Remove from the oven. Allow the crackle to cool completely on the pan. Once completely cool and hardened to the touch, break into bite-sized clusters.

Store: Store in an airtight container at room temperature for up to 7 days.