Heat oil in a deep-fryer or large saucepan to 375 degrees F (190 degrees C). Fry potatoes in batches in the hot oil until tender and golden brown, about 5 minutes. Remove to drain on a plate lined with paper towels.
Heat gravy in a small saucepan over medium heat until heated through, about 5 minutes.
Spread a layer of fries into two bowls, sprinkle with cheese and add a small amount of gravy; repeat these layers once. Squirt each serving with 1 tablespoon mayonnaise and 1 1/2 teaspoons ketchup. Sprinkle each bowl with half the lettuce; season with salt and pepper.
