The vast majority of recipes are derived from other recipes and combinations. The more ethical sources will be open about that. J Kenji Lopez-Alt, Andrew “Babish” Rea, and Alvin Zhou are VERY open about what inspired a given recipe whether it is another cook, a dish they had a t a restaurant, or just “tradition” and other cookbooks. Ethan Chlebowski and Brian Lagerstorm focus more on the underlying cooking techniques but will also generally credit the “inspiration”.

And then it is just iteration. Which is where Lagerstorm and Chlebowski are great sources as they had a semi-recent “podcast” where they made Taco Bell live or some shit and talked about how a single cheesecake video means they made cheesecake dozens of times over the course of a week or two.

This is WHY most of those recipe sites are hellscape blogposts. Because even the amateur chef likely put a couple hundred dollars worth of time and effort into that “ten dollar weeknight meal” and either they or the company that paid for the recipe need to try and make back some of that cash. Which generally means long ass blog posts for SEO and a shit ton of ads and affiliate links.