Overboiling, causing pierogi to burst
Pierogi require a lot of work, from making the stuffing to folding the dumplings, so it's extremely frustrating when one of them bursts open while you're trying to boil it. When you overcook your pierogi, this is more likely to happen. Many pierogi recipes will instruct you to cook them in hard boiling water. Very hot water will quickly cook your pierogi, but it's a bit of a high-wire act. Carolyn Beans, an NPR science writer, discovered through trial and error that lowering the heat after the pierogi have been dropped into the water makes it easier to avoid overboiling.
According to the Mashed pierogi recipe created in collaboration with food blogger Alexandra Shytsman, you should boil your pierogi in batches, filling the pot about 34 percent full each time. It's fine if the pierogi touch as they cook, but they should have enough space to separate. Freshly made pierogi usually take about three minutes to boil.