Put the new potatoes in a pan of lightly salted cold water, then bring to the boil and simmer for 10-15 minutes, until tender. Drain and set aside.
Press one garlic clove into a bowl, add the mustard, half of the thyme leaves, lemon zest, juice of half a lemon and a drop of oil. Pour this over the pork fillets - massage them well with the paste. You can marinate for up-to two hours, or whilst the potatoes are cooking and cooling.
Chop another garlic clove, then heat a spoonful of olive oil. Add the garlic and stir-fry for a few seconds then add the cabbage, half of the wine and put a lid on. Steam for 5 minutes, then stir-fry until all liquid has evaporated. Transfer the cabbage to a plate and keep it warm.
Add another spoon of oil to the pan. When hot, add the pork fillets and seal them on both sides for 30 seconds, then add the remaining wine and lemon juice.
Cook for 3-5 minutes on each side until golden, then transfer them to a plate.
Meanwhile, dice the potatoes or cut them into thin slices.
Add another drop of oil to the pan and the remaining garlic, finely chopped. Add the potatoes and thyme leaves , then fry them for about 5 minutes until golden, then put back the cabbage. Add the remaining wine and lemon juice. Stir gently, then put the pork on top.
Put a lid on and cook for about 3 minutes to warm through.
Serve warm with plenty of freshly ground peppercorn.