I have this device from Japanese dollar store Daiso originally meant for cooking Japanese-style soft-boiled eggs in the microwave. It’s really just a simple plastic cup with a built in sieve of sorts for easy draining of excess water away.
You’d crack an egg into the cup, fill it with enough water to cover the egg, then nuke it in the microwave for about 50 seconds. Drain the water away and you’re supposed to have a Japanese hot spring-style poached egg.
Except I have never got my eggs set to the desired doneness following the packaging’s instructions. After some trial and error with various cooking times and power levels, I pretty much gave up on using it for its intended purpose. Yolks were either overcooked or the whites remained too runny.
I then figured that cooking the egg at 70% of my microwave’s power setting for an additional 15 to 20 seconds resulted in a hard-boiled consistency, so this is my go to method for times when only a single hard boiled egg whose appearance is not a factor is needed rather than boiling it the traditional way.
If anyone were to cook this way, I would recommend some cling film loosely wrapped over the lid of the cooking receptacle though. There were a few times in my experiments where the egg kinda exploded. 😅