Wash and peel potatoes. Cut each potato in 4 parts lengthwise and slice each quarter into thin pieces. Repeat with the remaining potatoes. Place sliced potatoes in a bowl with cold water and let them sit there for at least 10 minutes.
Slice the onion into half or quarter rings, as thin as you did the potatoes.
Drain potatoes and place them on paper towel to dry. Use another towel to pat dry on top.
In a large cast iron skillet, heat sunflower oil over medium heat. Carefully add the potatoes in a single layer. Fry them for about 3 minutes on one side. Flip and add onions. Let them cook for another 3 minutes. Now stir the onions and potatoes carefully. Cover the pan with the lid and cook on lower heat for about 5-7 minutes or until potatoes are soft inside.
Uncover, turn the heat on medium-high and cook for another 3 minutes flipping potatoes a few times until they get golden-brown and crispy. Turn off the heat, add salt, pepper and chopped dill on top. Enjoy immediately!
*if you like, do not peel the potatoes*add more salt by taste*for crispier potatoes - soak sliced potatoes in cold water first and then, pat dry using paper towels.