You own your recipe. From the FAQs:
Do I own my recipes?
Yes, of course! You can use the recipes you upload to the site in any way you choose
You own your recipes, but if you repost someone else's recipe, be sure to give proper credit and don't just copy it verbatim. For the record, recipes cannot be copyrighted--if someone copies your recipe without changing anything--wording, amounts, etc.--you could potentially file a grievance, but even then it's a bit iffy (unless you do what Momofuku did with some of its recipes and copyright the name/idea, i.e. "Crack Pie"). Basically, recipes are not technically copyrightable.
If you wrote it you own it. However plagiarism can be punishable by law. And if you were David Ruggieri you would probably no the statutes by heart by now. Of course if you plagiarise in grad school it will get you expelled---I've seen it happen.
if you want to post someone else's recipe, the "right" thing to do is (1) ask for permission (you can contact individual cooks by clicking on their name) and (2) attributing the recipe back to the author (and Food 52 as the place where you first spotted it). If, for some reason, the author requests you don't repost, then don't.