I’m making blueberry muffins. We do not have a muffin pan, its a long story. We have a 13×9 pan and other pans. Is it okay to use a pan such as a 13×9 to make the blueberry muffins in? And do I still cook them at the same temperature?

Thanks for all of the help!
Also, we are planning on making like……a giant muffin.lol. Since we don’t have the muffin pan.