Peel the potatoes and cut them into quarters or eighths - depending on the size of the potatoes or according to personal preference. Bring to a boil in salted water, lower the heat, and cook for about twenty minutes until the potatoes are soft but not too much.
At the same time, cook the tagliatelle in salted water according to the instructions printed on the package. (tagliatelle is thinner than fettuccine).
Meanwhile, peel and finely chop the onion. Heat 4 tablespoons of oil in a large skillet or wok and fry the onion until translucent. Add minced garlic, Tear oyster mushrooms into 2 or 3 pieces, and add to onions. Saute them for a few minutes. Remove from the heat and let cool for 2-3 minutes. Mix in paprika, black pepper, and garlic powder.
Drain the pasta, drizzle a few drops of oil, mix, and transfer to the pan. Drain the potatoes, add to the pan, and mix. Taste and add more salt if necessary.
Divide into portions, sprinkle with chopped parsley or green onion, and serve.
