Originally, already a great build with a nice implementation of a PID controller with a nice touch interface, I just added where I could to make things faster and more reliable. I added a capacitive touch with a faster UI (courtesy of the TFT eSPI library), a heat sink to deal with the power dissipated by the solid state relay, a fix for the thermal switch in the toaster oven, and more.
*Note the case files will properly need to be checked and modified for your specific components. I say make sure to order all your stuff first and check their measurements before printing case. The thermocouple amp I made was custom-made and does not match with the Adafruit one so you will need to make changes there.