In a shallow bowl, whisk together the eggs and buttermilk. In another bowl, mix flour, salt, black pepper, garlic powder, onion powder, and paprika for the coating.

Dredge one cube steak in the seasoned flour, dip in the egg mixture, then coat again in the flour. Place on a wire rack and repeat with the remaining steaks, then allow to rest for 10 minutes.

Heat vegetable oil in a large skillet over medium heat to about 350°F. Test oil readiness with flour.

Fry the coated cube steaks for 3 to 4 minutes per side until golden brown. Transfer to paper towels to drain.

For the gravy, leave about 2 tablespoons of oil in the skillet, add butter, melt it, then stir in flour to form a roux.

Gradually whisk in whole milk, stirring until the gravy thickens, about 5 to 7 minutes. Season with black pepper and salt.

To serve, place a steak on a plate, pour gravy over it, and garnish with chopped green onions if desired.