The main difference between these two snacks is that the tortilla of a panucho is puffy, and may have white flour added to the masa and a salbute lacks refried beans. The marinated onions are essential and if they are authentic, they are prepared using the juice of a sour (Seville)orange. The meat is usually chicken, but can be turkey. Lettuce or cabbage and sliced tomatoes and avocado are garnished atop and you may notice a drizzle of media crema ( half milk/half cream) or a slice of hard boiled egg. They cost about a dollar each. Here is a very authentic recipe.