Dry the cubes of pork thoroughly and season with salt and pepper.
In a deep pan, add the olive oil if using, once heated up add the pork bites and brown for a couple of minutes each side.
Add in the wine and cook until only ¼ of the wine remains visible in your pan. Add the lemon juice, the liquids should just touch the top of your pork cubes.
Throw in the herbs, bay leaf and thyme, bring to the boil and then lower to a simmer. It needs approximately 30-35 minutes, with the lid on. Check again your liquids towards the last 10 minutes, if you think you are running out of liquids add some warm water.
If using mustard, add it in the last 5 minutes, be stingy with it though.