Peel the red peppers and cut them into strips. Cut the red onions into fine strips. Clean, rinse, and cut the chicken livers into pieces.
Heat 2 tablespoons of olive oil in a large pan over medium-high heat. Add the chicken livers and stir-fry for 4 minutes (be careful as they may splatter). Remove the livers to a plate.
Add the remaining 3 tablespoons of olive oil to the pan over medium heat. Add the onions and peppers and sauté for 3 minutes.
Pour in the white wine and simmer for 5-7 minutes, stirring occasionally, until the peppers are soft and the wine has reduced slightly.
Return the chicken livers to the pan. Season with salt and pepper. Stir in the balsamic vinegar and taste, adjusting seasoning as needed.
Sprinkle with chopped parsley and serve with rösti or mashed potatoes.