1. In small saucepan cook and stir barley and onion in butter over medium heat about 5 minutes or until onion is tender. Carefully stir in chicken broth and cinnamon. Bring to boiling. Reduce heat. Cover and simmer about 45 minutes or until barley is tender and liquid is absorbed. Remove from heat.
2. Meanwhile, lengthwise halve squash. Discard seeds. Place squash, cut sides down, in 12 x 8 x 2-inch baking dish coated with cooking spray. Bake, uncovered, at 350° F for 40 minutes.
3. Stir 1 cup of the cereal, apple, raisins and peanuts into the barley mixture. Add egg. Stir until combined.
4. Turn squash halves, cut sides up, in dish. Lightly sprinkle with salt and pepper. Spoon barley mixture into squash halves. Lightly crush remaining 1/4 cup cereal. Sprinkle on top. Bake, uncovered, for 20 to 30 minutes more or until squash is tender. Let stand for 10 minutes. Lengthwise cut each squash piece in half.