Recipe recommendations and menu planning essentially have the same problem on different scales. With recipe recommendations, there are a lot of different variations on a given recipe. With menu planning questions, there are a lot of different dishes you could decide to make. Either way, it's difficult to keep things objective and sufficiently brief to work in our format, and you end up asking people "what do you like to eat?" So both are routinely closed as off-topic.
For recipe recommendations, we have a canonical close reason:
Requests for recipe recommendations are off-topic; everyone has their own favorites. However, if you have a recipe already you can ask for help improving it - just be specific about what you want.
I sometimes apply this to menu planning questions, because it applies in a sort of fuzzy way: menu planning questions are asking for people to recommend a dish or recipe (or many of them), except minus the specificity of asking for a recipe for a single dish, so they're kind of like really bad recipe requests. But it's not perfect, and a couple times I've had people read it literally and say "but I wasn't asking for a recipe."
So: should we revise that close reason to more explicitly include menu planning? If so, what is your proposed wording?
Note: if you don't think that it should be added to that close reason, that's a totally fine answer. I'm not asking for a separate close reason in that case, though, because (a) menu planning is less common than recipe requests, so I doubt it merits a close reason all to itself and (b) we've already used our default allotment of 3 (nutrition/medical advice; recipe recommendations; what can I do with X) so we couldn't add an additional one even if we wanted to.
Another note: please take it as given that custom close reasons are a good idea, that we will use them, and we will strive to make them as good as possible. Any side discussion of whether custom close reasons are useful in the first place is out of scope for this question. If you wish to discuss that, please ask a new question.