1. Using a meat mallet or rolling pin, pound each beef cutlet to 1/4-inch thickness. Sprinkle garlic salt on both sides of each cutlet. Pour flour onto a pie plate or shallow bowl and coat each cutlet. Refrigerate until most of the flour has been absorbed, 10 to 20 minutes.
2. Pour buttermilk into a shallow bowl or pie plate. Dip each cutlet into buttermilk, then dredge each in another coating of flour, shaking off excess (reserve remaining flour for making gravy). Heat 2 tablespoons of the oil in a large nonstick skillet over medium-high heat. Add two of the steaks and cook until golden brown on both sides, about 4 to 5 minutes per side. Transfer to a serving platter. Repeat with remaining two steaks, adding remaining oil as needed.
3. Stir in remaining flour into skillet. Stir in broth, milk, salt, and pepper with a wire whisk. Cook, stirring constantly over high heat until thickened. Pour over steaks and serve. Makes 4 servings.