This is more a question of English grammar when using "conceive". According to http://www.thefreedictionary.com/conceive, "conceive of" (the accepted answer) is defined as "to form or hold an idea" and just "conceive" (transitive verb - not accepted by Duolingo) has as one of the definitions "To form or develop in the mind; devise".
I think the latter definition more closely translates this sentence, am I right?
Yes, but with some important warnings.
First, I would say most English speakers have dropped the "of" in the first sense of the word. "I couldn't conceive the immensity of my project" would mean something like "I couldn't imagine/understand. . ."
Second, I should note that the latter version of the English "conceive" as in "devise" is not heard all that often, with one exception: "to conceive a child." That does not mean to imagine or understand a child, it means to procreate, as in the physical act.
According to Oxford Dictionary, two of the collocations that goes with recipe are:
'To come up with' and 'To devise'
It also specify that the verb 'compose' is mainly used with 'music'
As such: 'The chef came up with-devised recipes' seem to be Oxford dictionary's only answers, although the latter verb is too formal.
I am dissapointed in Duolingo you used to have to type the sentences out yourself which gave users more practice. Also many things are translated badly such as this example "composed recipes" fr who says that? Theres tons of other examples people have reported. Honestly this is a downgrade.
You do will to type the answers up once you complete the easier levels and consolidate the new vocabulary. The update gives lots of extra practice at each level but you can skip this by testing out - just click on the key symbol. It's really a good upgrade once you get the hang of it!
No, that's ridiculous. If that is given as a correct translation into English, it needs to be fixed.
There is a very specific meaning for the verb "to couch", which is "to express verbally in a particular way". You might say that "The chef couched recipes in language meant to appeal to the snobbiest of gourmets", but using the verb without explanation would not be understood.