Good Start But Needs More Development
Firstly the Cooker should be able to be a device on a local WiFi network with proper secure login credentials rather than be a AP itself with weak security. This would mean that fiddling with the phone to change WiFi networks would not be required after initial setup.
Next, user entered recipes should be able to be sent to Thermo Cooker even if that is only one recipe at a time as it is being used and only stored permanently on your phone (not necessarily stored in the Cooker although that would be better). Once you are cooking I don’t want to be touching my phone I want to drive the Cooker from its own screen.
There should be a facility to import and export recipes from the App enabling sharing recipes across multiple devices.
Just these few simple additions in functionality would take this Cooker to another level that would greatly increase its appeal IMHO.