Season the steaks with salt and ground black pepper on both sides.
Add the butter and oil to a large frying pan, allow the butter to melt, and sear the steaks on both sides until golden, working in batches to avoid overcrowding the pan.
When the steaks are golden on both sides, remove them from the pan, and set aside.
Add the peeled and finely chopped garlic to the pan, and fry for 30 seconds to release its flavour.
Add the stock, herbs and mustard, scraping the bottom of the pan to release the browned bits, then simmer for 2-3 minutes.
Add a few tablespoons of the hot stock to the cream, and stir well, then add the cream to the pan.
Simmer the sauce gently for 4-5 minutes until it thickens, the add the pork steaks and juices released back to the pan.
Leave them to simmer for 2-3 minutes.
Season with salt and pepper and garnished with chopped parsley.