Step 1: Slice each chicken breast horizontally to create two thinner cutlets. Season both sides of the chicken cutlets with garlic powder, mixed herbs, salt, and pepper.
Step 2: Heat 1 tablespoon olive oil and 0.5 tablespoon butter in a large skillet over medium-high heat. Once hot, add the chicken cutlets and cook for 4-6 minutes per side, or until golden brown and cooked through (internal temperature reaches 165°F/74°C). Remove chicken from the skillet and set aside on a plate.
Step 3: Reduce heat to medium. Add the remaining 1 tablespoon butter to the skillet. Once melted, add the minced garlic and sauté for 1 minute until fragrant.
Step 4: Sprinkle the flour into the skillet and whisk continuously for 1-2 minutes to create a roux, cooking out the raw flour taste.
Step 5: Gradually whisk in the chicken stock, stirring constantly to prevent lumps. Bring the sauce to a simmer and cook for 3-5 minutes, or until it begins to thicken.
Step 6: Remove the skillet from the heat. Stir in the sour cream and ranch seasoning mix until well combined and smooth.
Step 7: Return the cooked chicken breasts to the skillet, spooning the creamy ranch sauce over them. Serve immediately.