As much as you can.
If you can put out 1000 high quality recipes by tomorrow, do it.
Just post the content when it's ready, and make sure it's good quality content.
You can't just glaze over this aspect. Putting out dozens of low quality recipes will do nothing for you - a single high quality recipe is worth 100 low quality recipes.
See: how to write a recipe post.
The day of the week myth
The myth that you should post on a given day of the week stems from email marketing, with some studies citing better open rates at certain times and on certain days. The take-away from that isn't that you should only post on a Monday - it was that you need to A/B test to find what works best for your customer-base - every industry is different.
But this doesn't transfer to food blogs. At all.
99.999% of your traffic is going to come over the months and years following your post. This means that the day that you post has basically 0% relevance.
The MAJORITY of your traffic is going to come from search engines and pins.
Nobody cares that you made a lasagna recipe this week.
They care about your lasagna recipe when they're ready to make a lasagna.
You can absolutely publish a Christmas recipe in July, but no matter what day of the week it is or how hard you promote it, you're not getting traffic to it until the holidays.
Years ago, there was a belief that you had to put out content "regularly" so that search engines knew your site was putting out fresh content.
This is not the case anymore (if it ever was).
Here's Google's John Mueller dispelling the post frequency myth:
Putting out content regularly to your social channels (Facebook, Pinterest, Instagram) is still a good idea, especially seasonally-relevant content. The great part about seasonal content is that you can re-use the same content year after year.
What makes quality content? The primary goal is to answer the reader query: how to make this recipe.
This requires not only great photography, thorough content and a tested recipe, but also great keyword research.
Use the Feast Plugins Recipe Update Checklist as a starting point for answering important recipe-related questions.
Gosh, thanks for this! I constantly stress about certain days to post new recipes and frequency, so this relieves some of that. My most popular recipe is one from years ago still to this day so I should know this but it helps hearing it from the experts!