Line a large baking tray with baking parchment. Drizzle with a little olive oil and use your hands to cover the surface. Separate the leaves of the sage and finely chop about a tablespoon. Set the remaining leaves aside.
Bring the stock to the boil in a large saucepan. In a small bowl whisk together the polenta and dried oregano.
Once the stock is boiling, reduce to a simmer and slowly pour in the polenta whisking as you do. Continue to whisk for about 3 mins then add the finely grated Grana Padano and chopped sage.
Continue whisking vigorously until the polenta is almost pulling away from the sides of the saucepan. The whole process should take no longer than 5 mins if you are using quick cook polenta.
Pour the polenta into the prepared tray and flatten with a spatula. If the polenta is sticking to the spatula just rub some olive oil on the spatula. Allow the polenta to cool then transfer to the fridge for an hour or so to firm up.
Invert the polenta onto a large chopping board an slice it into even sized pieces. I like to slice mine into large ‘chip’ pieces (roughly 1cm by 9cm).
To fry the polenta have a large baking tray lined with kitchen towel near by. Heat about 1inch of oil in a frying pan. Break off a piece of the polenta and add it to the oil to show you when the oil has reached optimum heat. When it is sizzling and browning you are ready to fry.
Add about 10 pieces of polenta to the oil at a time and fry for about 3-4 minutes until they are golden brown turning them half way through using tongs. Transfer to the kitchen towel lined tray to drain off any excess oil and season with sea salt. You may need to adjust the heat as you work through the polenta as the temperature of the oil will continue to increase.
Continue until the polenta is all cooked.
To cook the sage, reduce the temperature of the oil and wait for about five minutes. Drop a sage leaf in to test the oil. The leaf should sizzle but not turn brown. When a leaf is sizzling as it hits the oil you are ready. Add the sage leaves and cook for just 20 seconds. Remove carefully using a slotted sieved spoon or fork.
Pile the fried Grana Padano polenta onto a serving plate, top with the sage leaves and finish with a generous grating of more Grana Padano.
If you would like to make an aioli, whisk together the egg yolks, mustard, lemon juice and garlic in a bowl, then slowly add the oil whisking as you do until you have a thick glossy aioli. Taste to season.