Heat the oven to 200c or gas mark 6, pierce potato skins and bake for 45 minutes, once done, let cool.
Meanwhile cook the onions and chillies in a small pan for 8-10 minutes until soft and leave to cool.
Peel potatoes and add flesh to a bowl with chillies and onion, mash together with spices until smooth.
Using hands, mix in sweetcorn, coriander and half the polenta and season to taste. Shape mixture into 10 burgers, be careful as it can be quite soft, coat them in the remaining polenta and dust off any excess.
Place the burgers on the oiled baking tray and chill for 30 minutes. (They can also be frozen for another day at this stage.)
Can be cooked in the oven at 200c or Gas Mark 6 for 15 minutes or BBQ’d for 10 minutes on each side.