Step 1Heat the oven to 250 degrees. Line a half-sheet pan with parchment paper.
Step 2Combine the butter, oil, syrup, sugar and soy sauce in a small saucepan. Set over medium heat and stir until the butter melts and the sugar dissolves and stir until well-mixed.
Step 3Spread the cereal in an even layer and drizzle the butter mixture all over. Fold gently on the pan until evenly coated and spread in an even layer again. Sprinkle the furikake evenly over the cereal.
Step 4Bake, stirring once or twice, until dark golden brown and crunchy, 1 hour to 1 hour, 15 minutes. Stir once, then cool completely on the pan.
Sweet Crispix Arare: Substitute light corn syrup for the maple syrup and increase the sugar to 1/4 cup.
Chex Arare: Substitute rice Chex for the Crispix.