A few days...haha....it didn't even last an hour after i put it out. But yep, i did let it cool in the open oven...i used a cake pan though...instead of a springform..and i think once it rose around the edges...it sank back too far...but it tasted great. i just put a little whipped cream around the edges..i wasn't too worried about the cracking in the middle...makes it look homemade