It's an all clad paella pan. (Next time I'll use cast iron.)
Try using Bar Keepers Friend. Let it soak for a little before scrubbing. Hope that works!
ditto on the Bar Keepers - best ... stuff...ever. Use with a nylon scrubber.
Fill pan with water. Add a scoop of dishwasher detergent powder and a small squirt of dishwashing liquid. Bring to a boil. Boil 10 minutes. Cover. Leave overnight. Next day anything burnt or baked on comes off extremely easily. Has saved my pans (and me) many times. :)
Bar Keeper's Friend usually works for me, as does baking soda. If it is resistant to just scrubbing with baking soda, add baking soda and a little water to the pan (to cover the hardened oil) and boil for about 10 minutes. Let cool, or leave overnight, then scrub, much like EatArt's suggestion.
Thanks for the recommendations of Bar Keeper's Friend. I'd never heard of it before. I picked it up today at the hardware store and it worked like a charm! Amazing!
Fine steel wool. We're talking the superfine steel wool here. Sometimes you just have to weigh the outcome. A heavy burned oil film will laugh at whimpy methods.
I have an ancient 'no name brand' stainless pan..about 30 years old..and has been oil burned many times..and brought back using even simple brillo pads. It's still one of the best pans I have and great for omelets etc .
Just don't get too anal about the 'shine' on the pan, Good cookware is 'used' and sometimes looks that way.