Pound chicken with a meat tenderizer.
Season chicken with salt and pepper.
In a large skillet over medium high heat, melt 2 tablespoons of the butter with 2 tablespoons avocado oil. When butter and oil start to sizzle, add chicken and cook for 2 minutes on each side. Remove and transfer to plate. Repeat, adding more oil and butter as needed, until all the chicken is cooked.
Add the lemon juice, broth and capers to the same pan. Bring to boil, scraping up brown bits from the pan for extra flavor.
Return all the chicken to the pan and simmer for 2 minutes.
Transfer chicken to a platter.
Add remaining 2 tablespoons of butter to sauce and whisk vigorously.
Pour sauce over chicken and garnish with parsley.