:) Gnu, you have my sympathy too, at the time conversations like that make me want to tear my hair out
but my translation, in hindsight, might be

I'd like to cook whatever you want. I have almost anything available in my kitchen. You could look at the choices I typed out for you (months ago).
What are you having?(it would be nice to sit and eat the same thing together while we have a nice relaxed conversation)

I hadn't really thought about it. I'd like to know what you want.
What do you feel like cooking? (Well you haven't given me much time to think about it either. I'm happy with you just coming round and being here)
Whatever you would like.   
You decide.(something simple please. If you don't know a specific thing you'd enjoy cooking why do you expect me to know a specific thing I'd enjoy eating? )

Okay... I'll take out scallops for you.
Are you having scallops?(I feel patronised and awkward when the plates are different. And now you've mentioned scallops... actually I'm fairly sure I don't fancy them today )

No. I am going to have soup.
Well, I don't want you to cook scallops just for me.(I'd like to sit and have soup with you)

It's no problem. I would enjoy cooking scallops for you.
PAUSE................
No. I have things in my freezer I should use up. I was planning to have the Swedish Meatballs you cooked last weeks. I froze what I couldn't eat and I really should use them up because I don't want to keep them in the freezer too long. If I keep them in the freezer too long they lose their taste.....(No, now I don't fancy scallops. OK, I'll make a damned decision for you. The only food that comes to mind is the meatballs in the freezer. I'd better make up some good reason for choosing them)

..... two minutes later....   Okay, no problem.   I hang up the phone and fucking scream.
- silence (I'd just like like to see them. Maybe we could have a glass of wine with the meatballs and chill out a while.
Maybe I would have enjoyed scallops. I'll make a note and ask for them next time.)
////////////////////////////////////////
I'm coming round later and I wondered if you had anything in mind you'd like to eat. I wondered about a little bowl of soup I've already cooked and need to use up .......and then scallops cooked that way you like. But if you think of something different you fancy call me back in the next 30minutes -Oh, there might be something else on that list I left you.
That'd be lovely dear. I only really get an appetite once I smell your lovely cooking.(I only really get an appetite once I smell your lovely cooking... and anyway when I try to read that list at this time of day my eyes glaze over and I feel stressed)

Then give yourself a lovely big bowl of soup, a little plate of scallops & leave what you can't manage in the fridge/freezer.

Hmmm, easy in theory. I know reality always ends up different from my dreams.