Start with slicing your chicken breasts in half horizontally to make cutlets. This ensures each piece cooks quickly and evenly. Season both sides of the cutlets with garlic powder, black pepper, and salt. Then, lightly dredge each cutlet in flour, shaking off the excess.
Heat one tablespoon of olive oil and two tablespoons of butter in a large skillet over medium heat. Once the pan is hot, lay the chicken in a single layer. Sear each side for about four minutes or until golden brown. The chicken should be fully cooked with an internal temperature of 165°F. Set it aside on a plate.
Using the same skillet, add the remaining butter and sliced mushrooms. Saute them over medium heat for about four minutes until they release their moisture and turn golden. Then, stir in the capers and cook for an additional minute.
Deglaze the skillet by adding chicken broth and lemon juice. Stir the mixture well to combine all the flavors. Bring it to a gentle boil, allowing the sauce to thicken slightly.
Return the chicken cutlets to the skillet, spooning the warm sauce over them. Reduce the heat to low and simmer for a few minutes to reheat the chicken and soak up the flavors. Garnish with fresh parsley before serving.