Adafruit forum user wolfer649 posts their oven/appliance controller:

This is a standalone Raspberry Pi, Adafruit-based hardware assembly project and associated Python software that can be used to measure, chart and record appliance temperatures over time.

Hardware

The modestly named World’s Greatest Oven Thermometer (WGOT) consists of three, stacked subassemblies.

1. A Raspberry Pi3 B+ bottom board

2. An Adafruit Perma-Proto Hat with MAX31855 stamp & connections – middle board

3. An Adafruit 2.8″ PiTFT capacitive touchscreen, with buttons, on top

On the the 2.8″ PiTFT capacitive touchscreen, this device will show the current temperature, with the option of an additional save/hold temperature value or even a graph of the temperature over time.

The selections are made by pressing associated buttons on the PiTFT screen board and by touching the PiTFT screen.

– You can reset the timer, in case you want to start recording again – say after a false start or changing adjustment values.

– It creates a csv log file that can later be used offline, to build fancy graphs or spreadsheets for analysis purposes.

– Optionally, this Linux-based device can be shutdown and/or restarted at the touch of a single button, to avoid having to remove and replace the power supply connection.

– There is a handy flashing LED activity indicator, so that you can check if the software is alive: especially useful in “headless” mode.

– No Internet connection is required, because all of the timing is relative.

– Typical CPU utilization is less than 10% on a Raspberry Pi 3 B+.

The beta software and associated hardware/software documentation can be found at https://github.com/wolfer649/WGOT.

For development purposes, the software can be tested on an attached X11 HDMI screen/keyboard (or via VNC) without access to the Adafruit PiTFT itself, by changing a single Python statement, though you will need the Adafruit Perma-Proto PiHat board with the Adafruit MAX31855 board attached to it.