I think that simply promoting good vegetarian meals would potentially reduce meat consumption among certain groups of people that would be less receptive to accompanying pro-vegetarian arguments. I think it should be part of a vegan-advocacy arsenal (i.e. you do a bunch of different sorts of flyers/ads/promotions, some of which is just recipe spreading without any further context)

However, if one of your goals is to increase human compassion for nonhumans, then recipe spreading is dramatically less useful in the long term. One of the biggest arguments (among LW folk anyway) for animal advocacy is that not only are factory farms (and the wilderness) pretty awful, but that it'll hopefully translate into more humanely managed eco-systems, once we go off terraforming or creating virtual worlds.

(It may turn out to be effective to get people to try out vegan recipes [without accompanying pro-vegan context] and then later on promote actual vegan ideals to the same people, after they've already taken small steps that indirectly bias themselves towards identifying with veganism)