Hi,
My Oxford dictionary offers this.
subsequent (adj) followinga specifed event etc,. in time, especially as a consequence. subsequently (adv)
Could you give me an example of 'subsequently' used for future? I'm going to complete my M. Sc. in 2010. Subsequently, I'm going to apply for medical school.
'Subsequently' does not fit your cooking examples, because there is no hint in them of 'consequence'. In addition, it is too 'fancy' a word.
"First cook the onions, then add the mushrooms."
Can I use afterwards, subsequently, or after that in the sentence above instead of 'then'? Yes, but 'then' is best, because it is short and simple. You could also say 'next' or 'now'.
For example,
First cook the onions, afterwards add the mushrooms.
First cook the onions, after that add the mushrooms.
First cook the onions, subsequently add the mushrooms.
Are 'afterwards', ''then', 'after that' and 'subsequently' interchangeable in the following sentence? 'Subsequently' is good here, because it suggests 'later in time' and 'consequence'.
"Not only did I vomit, but I had the runs. Subsequently/After that/Afterwards/Then, I went to see a doctor."
Best wishes, Clive