Start by grating the parmesan cheese. Keep it in your fridge for later.
Then mix the vegetable broth (1) with the butter, the salt and the polenta. Mix it well and while stirring bring it to a boil. Let it boil for 2 minutes.
After that add the grated parmesan cheese and mix it once more. Then pour it on a tray and let it set in your fridge.
Now portion it into more manageable pieces and transfer it into a blender together with the vegetable broth (2). Blend it till smooth. Insure it a 100% smooth, otherwise pass it through a fine sauce sieve.
Then fill your syphon and charge it with 1 charge. You can keep it in your fridge for three days.
To heat it up just reheat the syphon in a heat draw or in a pan that filled with warm water. Super easy and no fuss! Once warm or hot it’s ready to be served! If you want a thicker espuma add another charge and shake it well.