Your husband achieved a two-for He destroyed two appliances simultaneously. It is not going to come off.

Wow. How about heating the plastic with a blow dryer or a heat gun until it's soft and scraping it with a plastic scraper? In a pinch, a credit card might do the trick but a scraper with an edge would do a better job.

Get what you can up and use a soft abrasive cleaner (bar keepers friend) for the residual.

I've used a razor blade window scraper to get up boiled over and burned mess. Didn't hurt the cook top.