Blocked senders keep appearing in iPad Mail inbox

Sadly, if your email address is being used as a target for spam, there is little that you can do to stop it; anyone that has your email address can send email to to. Instead you have to “manage” it…

First, be wary of any “unsubscribe” links that may be embedded in the email messages. For the most part, unless the unsolicited email is from a reputable source/advertiser, the unsubscribe link will not necessarily stop the messages. Instead, clicking the link will simply confirm to the spammer that the email address is monitored by a warm-blooded victim - and more spam and unwanted content is likely to come your way.

For unsolicited email, you can use the native blocking feature of iOS/iPadOS to automatically block/delete unwanted email from a sender - although this will only be effective for spam that arrives from a consistent email address:

Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch - Apple Support

Where the spam email is using “spoofed” email sender addresses, your block-list will be ineffective.

The best advice is to avoid becoming a victim. Be careful where you use your email address to subscribe to services. Perhaps keep a secondary address just for this purpose - or, if you have updated to iOS/iPadOS15.1 or later, consider using Apple’s new Hide My Email facility:

What is Hide My Email? - Apple Support

Set up and use Hide My Email in iCloud+ on all your devices – Apple Support

Again, this new feature cannot stop everything, but is another way to reduce the likelihood of receiving and managing email and messaging spam. 

The emails from this cooking scam page mostly start with "cooking@sp". I created a temporary address for that in Contacts, then added it to the blocked senders because to add an address requires an address in Contacts. (Cannot write in a new address directly into blocked senders.) Then deleted it in Contacts. We'll see. Would be nice if we can add a wildcard character in the address (cooking@sp*.com) but I read elsewhere that this is not supported in Apple Mail. There is also this guidance about using Return Path to deal with the problem, Wild card in apple email rules - Apple Community

I get trash from some of these as well. I tried unsubscribing which in retrospect was likely a mistake as it let the sender know someone on the other end paid attention to the spam. I tried blocking the sender address but they change those address details occasionally.

So I live with it, and send the messages to junk.

If you’re ambitious perhaps you can devise a shortcut to deal with this. Here’s how:

Shortcuts User Guide - Apple Support

I am not that ambitious.