Preheat the oven to 200C, or 400F degrees.
Salt and pepper both sides of the pork slices.
In a oven proof casserole that has a lid. Take the oil and heat until hot and brown the pork on both sides. Do that in 2 batches if you need to. Don't crowd the pot.
When the pork has been browned return it all to the pot. Mix the water, vinegar, sugar and thyme together, mix well and then pour it over the pork. Add the garlic and bay leaves, bring to the boil, cover and place in the oven and roast for 1 hour.
Remove from the oven and take the meat out of the pot and set aside. Boil the contents of the pot down until you have a little more than 2.5 dl or 1/2 cup of liquid.
You can cook this up to this point and warm it up later.
If you are serving it right away. Toss in the chopped parsley, 2 tbls of cold butter and whisk it into the sauce. Correct for salt and pepper.
Return the meat back to the pot or a serving dish and serve.