Seasoning is often the feared enemy of many amateur cooks. However, once you understand the underlying theory, it's quite simple.
Therefore, the most important message first: flavor is formed by [restrict]salt and acid. If both are missing, even the strongest food tastes bland and boring. That's the answer to "There's still something missing!": Try adjusting the taste of your creations with a bit of salt and acid. In other words, the ratio of