It's certainly an interesting conundrum, Stacy! We actually just shared a blog article about The Art and Science of Popovers, that goes through the whole process. Usually, a popover will pop straight up in pans with straight sides, like a popover pan. Muffin tins create more of a "mushroom" style popover with a more rounded top. No matter which pan you used, it sounds like until now, your popovers have had the mushroom-like appearance.
The most likely cause for this strange "pop" is that the oven temperature was possibly a bit too hot. This would cause them to rise SO fast that they rise straight up! If you don't have an oven thermometer, grabbing one to just double check the temperature in there might be the key. Most ovens are a little wonky so it could be running hotter than it says. Let us know how the next batch turns out! Annabelle@KAF
June 19, 2018 at 2:15pm
In reply to After baking many perfect popovers in my commercial gas oven, I… by Stacy Cooper (not verified)