Heat the cooking oil and butter in a wok or frying pan. Add the pork and cook, tossing often, until the edges start to brown.
Throw in the sweet potatoes. Sprinkle with salt and pepper. Continue cooking, tossing occasionally, until the edges of the sweet potato cubes start to brown as well.
Add the peas to the pork and sweet potatoes and toss. If they are frozen, you'll have enough liquid to create the steam needed to cook the sweet potatoes until tender. If the peas had been thawed, add a couple of tablespoonfuls of broth or water to the pan. Cover the pan, lower the heat and cook until the sweet potatoes are just done. It should take about 10 minutes after which the mixture should be almost dry.
Add the sliced onions. Toss for half a minute.
Pour in the yogurt and honey. Toss until the liquid has soaked up by the meat and vegetables.
Taste and add more salt and pepper, if needed.
Turn off the heat. Add the parsley and toss a few more times. Serve hot.