In a medium skillet, heat margarine or butter. Add onion, green onion, and jalapeno pepper; cook for 3 to 4 minutes or until onion is tender. Stir in corn. Cook and stir until heated through.
Layer 12 of the bread slices in the bottom of a lightly greased 2-quart square baking dish. Top with corn mixture. Place remaining 12 slices of bread on top. Combine eggs and milk in a medium mixing bowl. Carefully pour over layers. Cover and chill for at least 2 hours or up to 24 hours.
Bake, uncovered, in a 350 degrees F oven about 45 minutes or until lightly browned and set. Transport in an insulated carrier. If desired, garnish with fresh herb sprigs, green onion curls, and red pepper strips. Makes 12 side-dish servings.