1. Set out a small mixing bowl and combine the brown sugar and Apple Pie Spice. Stir the sugar and spice until well combined.
2. Open the large brown bag and measure the 2 cups of powdered sugar into the bag. Add in the Spice mix.
3. Pour the rice Chex into a large mixing bowl.
4. Using a medium microwave-safe mixing bowl add the Dulce de Leche. Microwave for 30 seconds, stir and return to the microwave for 30 more seconds.
5. Pour the Dulce de Leche into the rice Chex and stir until the cereal is completely coated. Once coated dump into the brown back with the sugar mixtures. Close the bag and shake it up. Check to see if the cereal is coated completely, if not continue to shake.
6. Once all the cereal is coated pour it out onto a baking sheet covered in wax paper.
7. Let the puppy chow completely dry- for about 1 hour then put it into an airtight container.