Thinly slice the red bell pepper and dice the yellow onion. Thinly slice the pepperoncini peppers into rings. Finely grate the Parmesan cheese.

Cut the chicken breasts into ½-inch-thick slices and toss with ¾ teaspoon kosher salt and black pepper.

Heat 2 tablespoons of olive oil in a skillet and cook half of the chicken until browned. Transfer to a plate and repeat with remaining chicken.

Add remaining olive oil, bell pepper, onion, remaining salt, and Italian seasoning to the skillet. Cook until beginning to brown and add chicken broth.

Add Parmesan and heavy cream. Bring to a simmer, then return chicken to the skillet and add pepperoncini, tossing to coat.