Add 1 or 2 tablespoons of extra virgin olive oil, depending on your habits. Do not add salt.
Stir the chopped onion until it turns slightly “golden”.
Place the pork loin in the pan and turn the heat to max temperature. Let it cook for about 5 minutes.
Turn the loin upside down and let it cook for 5 more minutes!
Reduce temperature to a minimum. Pour the full-fat milk into the pan.
There’s not an exact quantity of milk. It simply has to cover quite completely the fillet. In my case, I used 3 pints of full-fat milk. Do not add salt.
Add 2 laurel leaves to give a more Italian flavour, and let it cook for about 1 hour and a half at a very low temperature depending on the dimension of your fillet.
If you think the loin is cooked, but your sauce is still too watery, pick up the fillet.
Add 1 teaspoon of flour (gluten-free if needed) until the sauce thickens. You won’t have to wait to choose if to add some more flour or not; the sauce will start thickening right away.
Whether you use flour or not, the milk at this point should look like a lumpy cream. With a spoon or a fork, crush the lumps and mix it with the remaining sauce.
Add a pinch of salt. Stir well.
Once the milk is wholly reduced into a sauce, cut the pork loin into slices and serve it with its sauce and top with pepper.