PLEASE REMEMBER THIS IS A BOARD WITH HIGH CURRENT AC POWER! YOU MODIFY AT YOUR OWN RISK.
I've added pics of the breadboard and attempted to make a fritzing schematic, let me know if I've stuffed (see f'ed) it up.
Now this model kettle has some benefits and some drawbacks in comparison to the Bonavita BV382510V.
The Bellini Digital Kettle - BTK615 is cheaper at AUD$49 and has a nicely available 5v power supply that plays well with a nodeMCU v1.0. It does not work with a D1 mini, as we are not using the USB port for power. (however if you wanted to put your own power supply in like Luma did go right ahead but I think it would end up bigger than the nodeMCU).
Speaking of power...
The LED that indicates the kettle is on is PWM controlled. That took some time to figure out but a really good learning experience for me.
Blue is the power LED anode and white is the power LED cathode, the switch is directly below it and I made a mess of soldering the cables the wrong way around, it would of been better having the switch cables facing the opposite direction as you may notice the insulation has a mark on it and maybe at risk of melting if in prolonged contact with the LED pins.
More pics for perspective.
So here is the breadboard. I did put the cables in a connector but I don't count so good.....
I'll be attempting a Fritzing diagram soon.
Its really hard to get anything done in a small house with 3 kids trying to take over my PC. I know this looks a mess but I'll update it when I get some time. Hopefully night shift at work will give me time update the code too.
I wrote the code to connect to my Home Assistant server via MQTT. So it monitors the state of the kettle via the the "boiling" LED and has birth and last will messages. This kettle goes into low power mode after 2 hours of inactivity but is nice enough to still leave the 5v going to the ESP8266 to allow it to wake it back up again, however that takes about 8 seconds to update to the MQTT server. I'm pretty sure I trapped all the spam buttons.
The drawback is that I can't seem to turn it off. I'm not really that good with electronics but I didn't feel the need to turn off the kettle that I just turned on enough to solve that problem. It turns on and traps any requests to turn it on while its already on so that was enough for me. I do have intentions to add the WiFi manager in instead of hard coding the SSID and credentials as if you have to change your SSID or password you would have to pull it apart and connect the usb cord to change it. Also the deep sleep function that Mike suggested would be good.