In a large skillet over medium heat, add a drizzle of olive oil and sauté the diced onion and minced garlic for about 3–4 minutes until the onions turn translucent.

Increase the heat to medium-high and add the chicken breasts, searing them for 5–6 minutes on each side until golden brown and cooked through.

Lower the heat to medium, add the sliced pepperoncini and chicken broth, stirring to combine. Bring to a gentle simmer for 2–3 minutes.

Slowly pour in the heavy cream while stirring continuously. Allow the mixture to simmer for about 5 minutes until thickened.

Return the chicken breasts to the skillet, coating them in the sauce and simmering for another 2–3 minutes.

Remove from heat and serve hot, garnished with parsley or parmesan cheese if desired.