Meanwhile, sprinkle both sides of chicken evenly with garlic powder, salt and pepper. Dredge chicken in flour in a shallow dish; shake off excess. Set the chicken on a plate and repeat with remaining chicken.
Heat 2 Tbsp. butter and 1 Tbsp. olive oil in a frying pan over medium high heat.
Once hot, place chicken cutlets in pan (do not crowd the pan) and brown on each side, about 3 minutes per side. Remove the chicken from the pan and set on a new plate. (Chicken will not be fully cooked yet, that's OK)
Turn the heat to medium-low and to the same pan, add in the capers, lemon juice, white wine, and garlic. Whisk in remaining 2 Tbsp. butter. Use a spatula to scrape up the browned bits if needed. Bring the sauce to a simmer and then thicken by adding in a cornstarch slurry: 1 Tbsp. cornstarch mixed with 1 Tbsp. water. While the sauce is simmering, mix the water and cornstarch together in a small dish and whisk into the sauce. Continue to whisk, the sauce will begin to thicken.
Place the chicken back into the pan, spoon some of the sauce over the chicken. Place a lid on the pan and turn heat to low. Let cook for 10-15 minutes or until chicken reaches an internal temperature of 165°F.