On medium heat, add a drizzle of oil and line up dumplings in a non-stick pan.
Meanwhile, mix together water, flour, cornstarch, and sesame oil. Pour over dumplings and cover to steam. The steam time will depend on your type of dumpling. Refer to the instructions on the frozen package. Mine usually says around 8 minutes.
Once steamed, remove the lid and let the rest of the water cook-off. This will require patience because you don't want to move the dumplings until all the water has cooked off and the bottom is looking crispy. You'll know when it's ready when you pick up the pan, gently shake, and everything slides together in one piece.
Now, place a cutting board over your pan and carefully flip to invert. The trick here is confidence. You got this!