Official Contest Entry: Simply Potatoes 5Fix. Popovers are so delicate and delicious. I frequently add grated cheese to mine, so I figured they would be great with macaroni and cheese. The best tip I ever got when it comes to making popovers is to never, ever open the oven door while they cook. It could cause your beautiful popovers to collapse. Another key to success is to preheat your empty popover or muffin tins and work quickly to get the filled pans back in the oven. Also, I've always gotten the best results by using all ingredients for the batter at room to lukewarm temperature.