I am not a lawyer. But it's my understanding that recipes, in their barest form, cannot be copyrighted, as they are a description of a method of accomplishing something. What IS copyrightable is the specific text that expresses those instructions, as well as any accompanying images, etc. There may be other aspects of the way the recipe is organized that is copyrightable. Scraping a website, yielding identical text and images, will surely fall afoul of copyright law, if nothing else for the images alone. The directions of the recipes may be purely descriptive of a process or may be more creatively expressed; the creative ones will also trigger copyright protection.
Thus, as I understand the laws, I can publish on my blog or in a cookbook any recipe I want, as long as I express it in my own words and use my own images.
You should consult with a lawyer regarding recent decisions on the copyright of data. For example, the Yellow Pages company often tried to copyright the contents of phone books to prevent competitors from producing similar listings. They've had mixed success. See, for example, this blog post which addresses UK law and which suggests that databases, that is, collections of electronically-accessed data, are offered at least some copyright protections. This means that scraping a competitor's site might be illegal even if none of their content is individually copyrightable. I'm not up to date on the US laws or the laws in other jurisdictions on this matter. You could be on shaky grounds. The laws might be contradictory: it might be the case that simply making a database of public-domain works makes it difficult or impossible for others to do the same. Such is copyright law in this age.
The best way to build a collection of recipes is to curate the initial collection manually. No matter where you get the recipes, review each one, rewrite all the copy, test them to see that they work, adjust the language to account for regional differences (i.e. I hate it when a recipe calls for, eg, a stick of butter... I have never seen butter sold in sticks.) Once you have a collection of recipes you've actually worked on, I am pretty sure all legal and ethical concerns would be alleviated. As usual, the easy path is not the best path.