Line a 34cm x 24cm tray with baking paper and set aside until needed.
Place the garlic, parmesan cheese and cheddar cheese into the Thermomix bowl and grate on Speed 9, 10 seconds. Set aside in a seperate bowl.
Add the vegetable stock and heat for 8 minutes, Varoma, Speed 2.
Set the Thermomix to Varoma, 3 minutes, Speed 2 and slowly add the polenta through the MC hole (while the blades are turning) and replace the MC once done.
Add the butter, cheese and garlic cloves and salt and slowly increase to Speed 7 for 1 minute (if the Thermomix starts shaking, turn the Speed down and continue to increase slowly).
Working quickly, pour the mixture into your prepared baking tray and place a sheet of baking paper over the top before placing another tray on top to keep it flat. Place into the fridge for one hour to chill.
Pre-heat your oven to 200 degrees once the mixture is cold and cut into 'chip' size pieces. Place these onto a baking tray covered with baking paper and cook for 30 minutes or until crisp and golden.