In a shallow bowl, whisk together the milk and egg until thoroughly combined. Set aside.
In another shallow bowl, mix the flour, crushed saltine crackers, seasoned salt, onion powder, garlic powder, and Montreal steak seasoning. Stir until the seasonings are evenly distributed throughout the breading.
Dip one cube steak into the egg and milk mixture, coating both sides. Lift it out and allow the excess liquid to drip back into the bowl.
Transfer the steak to the seasoned flour mixture. Press the coating firmly onto both sides until the steak is evenly covered.
Place the breaded steak on a clean plate without stacking. Repeat the dipping and coating process with the remaining cube steaks.
Heat the vegetable oil in a large skillet over medium-high heat until hot.
Carefully place the coated steaks into the skillet in a single layer. Cook in batches if necessary to avoid overcrowding.
Fry for approximately 4 minutes on the first side, until the coating becomes golden brown and crisp.
Carefully turn the steaks and cook for another 4 minutes, or until the second side is golden and the meat is firm and hot throughout.
Check the internal temperature with an instant-read thermometer. The supplied recipe specifies 160°F (70°C). Remove the steaks once they are safely cooked, and serve warm with country gravy and mashed potatoes.