They would mean the same thing to me, but it would be strange for something like a cooking recipe to say 'amalgamated'. That word's usually used in more scientific circumstances. For example, you would mix the ingredients of a cake, but you would amalgamate the elements of an alloy.

The difference is the context in which the words are used. "Amalgamation" simply isn't used in cooking. However, I suppose that if you are in training to become a sorcerer, it might be a useful word 😊