Melt the ghee in a large cast iron skillet over medium-high heat. Add the leeks, garlic, tomato paste, and thyme to the melted ghee. If you don’t have fresh herbs, just shake on some dried ones! I cooked the leeks until they were softened and lightly browned (8-10 minutes). Stir in the tomato paste.
Add the chicken stock and vermouth to deglaze the pan.
Chuck the leek mixture along with the tomatoes, carrots, and celery into the slow cooker. If you are adding cabbage, tuck it in around the roast. Sprinkle in about a tablespoon of Red Boat fish sauce.
Dry off your roasts, take off the elastic netting, and season them liberally with salt and pepper. If you have the time, it’s best to season your pork overnight to get the best flavor.
Tie up your roasts with twine and nestle them into the slow cooker. Cover the cooker and set it to cook on low for 9-11 hours.
After the roast is finished cooking, fish out the two roasts and put them on a cutting board to rest.
Remove the thyme twigs from the pot and use a large spoon to degrease the braising liquid. Add in the vinegar, fish sauce, and salt and pepper to taste. Then, shred up the meat, serve it on top of the veggies, and pour on the braising liquid.