Grease two 18X28cm rectangular slice tins and set aside.
Place the parmesan cheese and cheddar cheese into the Thermomix bowl.Grate for 10 seconds, Speed 9, 10 seconds. Set aside in a seperate bowl.
Wash and dry the Thermomix bowl.
Add the rosemary leaves and garlic to the Thermomix bowl.Finally grate for 10 seconds, Speed 7, 10 seconds. Scrape and repeat until finely chopped.
Add the water and heat for 8 minutes, Varoma, Speed 2.
Set the Thermomix to 3 minutes, Varoma, Speed 2 and slowly add the polenta through the MC hole (while the blades are turning).
Place the MC lid back on (to prevent any mixture bubbling out).
Add the butter, cheese and sea salt and slowly increase to Speed 7, 1 minute (if the Thermomix starts shaking, turn the speed down and continue to increase slowly).
Quickly pour the mixture between the two prepared tins and place onto the bench to set for 20 minutes.
Place into the fridge until completely cold.Cut into 'chip' sized pieces.
At this stage you can either bake the polenta chips on a baking tray in the oven (200 degrees celsius fan-forced) for 20-30 minutes or until crispy on the outside, or you can freeze them in an airtight container (with a sheet of baking paper between each layer).
The polenta chips can then be cooked as per usual from frozen.
Notes
RECIPE NOTES & TIPS
Fresh rosemary sprigs will give you the best flavour, however, dried rosemary can also be used.
The combination of parmesan and cheddar cheeses gives the polenta chips the most delicious flavour.
Once you've mixed the polenta mixture until creamy, work quickly to pour it into the prepared baking tins (it will set quickly).
Allow the chips to cool before cutting into 'chips'.
Store in the fridge for up to 3 days.
You can oven bake the polenta chips immediately or freeze them for another time.
If freezing, add a sheet of baking paper between each layer of chips and store in an airtight container for up to 3 months.
The polenta chips can be cooked directly from frozen.