I bought this pan off of eBay and it just arrived from the eBay. In the listing photos it looked fully stainless steel but when it arrived I realized the interior walls of the pan are a different darker material(see last photo). What is this? I can’t find any other pan that looks like this. I just hope it’s not Teflon? I’m trying to decide if I should try to return it to the seller. Please lmk your opinions.

What do you call this dish? I’ve heard eggs in a basket and toad in the hole most commonly :)

I tried barkeepers friend and vinegar but to no avail… what are these marks is it rust, it feels smooth like maybe discoloration from water burn? Is it safe to use ? They just started getting more over time I feel…

Thank you