I thought I would throw in a vote for the crockpot/slow cooker. My dinner is cooking as I type. & later I’ll be able to watch the Australian version of Master Chef intead of slaving over a hot stove which is what I would normally be doing at 5.30pm.
If we are talking about food my vote goes to the olive & the long ago genius who discovered how to make them edible. 
There is a recipe in my breadmakers manual, and a setting on the breadmaker. I’ve used frozen peaches. You just dump the fruit in, add sugar, pectin, spices (cloves, cinnamon, etc), lemon juice. Use “jam setting”. Thirty or so minutes later you have fresh (hot) jam. Serve with freshly baked bread!
I remember Phil Harris’ remark to Frankie Remley: This will be the greatest thing since Whitney squeezed gin out of cotton!
Now,that is amazing.
Cooking it?
Me too. Developed by Norman Borlaug. Norman Borlaug - Wikipedia
I second that vote! The cognitive leap between “Don’t touch, it’s hot!” and “Hey, if you hold food over this stuff, it’s easier to digest (and, incidentally, has fewer live pathogens than before)” was incredible. Everybody understands that heat burns things, but the first guys to invent cooking were really onto something! Cite.
Bacon Salt!
Beer. Civilization couldn’t have happened without it.
Those pre cooked rice bags. Stick’em in the microwave for 90 seconds and voila, you got perfectly cooked rice. With no frick’n mess!!
RIP Norman Borlaug!