Add the maple syrup, butter, cocoa powder, and salt to a large saucepan (big enough to also hold the rice), and simmer until the salt is dissolved and the cocoa is blended in.
Cool the maple syrup mixture for a minute or so and then blend the puffed rice. Blend until well-coated.
Spread the mixture across a cookie sheet and place it in an oven preheated to 350°F/175°C. Bake for about 10 minutes, or until it is crunchy when cooled. To test for crunchiness, take out a small amount from the oven to cool for a moment.