Start by peeling the onion and slicing it into rings.
Pat the chicken livers dry with paper towels, cut them in half, and trim off any visible fat or green parts and wash hands.
In a large skillet, heat the olive oil over medium heat until it shimmers, which should take about two minutes.
Add the onions to the skillet and season them with half the kosher salt.
Sauté the onions, stirring frequently, until they turn golden brown, about ten minutes.
Once done, transfer the onions to a plate and cover to keep warm, or place them in the oven on a “keep warm” setting if available.
In the same skillet, add the cleaned livers and season with the remaining kosher salt and ¼ teaspoon of black pepper.
Cook the livers over medium heat for about three minutes per side, until they are browned on the outside but still slightly pink in the center.
To serve, divide the cooked livers onto plates, top them with the sautéed onions, and enjoy.