Preheat your oven to 140°C.
Use a Dutch oven or a casserole dish with a lid and put it on the stove over medium-high heat.
Trim off any excess fat and sinew, and season them well with salt and pepper. Brown them on both sides in a large skillet over high heat, until they are caramelized and golden.
Do this in two batches if needed, to avoid overcrowding the pan, and making sure you get some good color on the meat.
Remove the cheeks and reserve on a plate Turn the heat down to medium.
Add some more oil and then throw in the mirepoix: onion, carrot, celery, + garlic mushrooms and oregano, cover and sweat for 10 minutes until everything is soft.
Pour the red wine into the pan and scrape up any browned bits from the bottom. Let it simmer for about 3 minutes to evaporate the alcohol, then put the cheeks on top of the vegetables again.
Add the tomato sauce and the chicken stock to the casserole and bring it to a boil. Then, cover the casserole and transfer it to the oven.
Cook for 2.5-3 hours, checking every 30 minutes starting at 2 hours, and flipping the cheeks, when you do. They should be very soft and starting to fall apart when done
Strain the sauce from the pork cheeks into a saucepan, using a sieve or chinois and pressing hard with a spoon. (if you want to reduce the the sauce) Cover the pork cheeks and keep them warm. Or just serve.
Cook your polenta according to the directions. Chicken stock will give more flavor than water.
Adding some pepper and a Tbsp of butter as the final touch will kick up the flavor.
To serve, spoon some warm polenta on each plate and top with one or two sliced cheeks. Pour some of the rich sauce, mushroom over them.