Below you have all the parts needed for this project. The Arduino has a 5V regulator, so we can use the small 220VAC to 12VDC converter and supply the Arduino on the RAW pin with 12V and it will regulate its own 5V for the rest of the difital part. Use the K type thermocouple and the MAX6675 amplifier to measure temperature. Use a bigger SSR if you want more power, the one I've used is 2A and 220V so around 450W. You could easily find relays up to 40A at 220V so around 8000W.