Preheat your air fryer to 400°F. Toss the diced red potatoes with 1 to 2 tablespoons of olive oil, salt, and black pepper. Air fry for 16–18 minutes, shaking halfway through for even crispiness.

In a skillet over medium-low heat, add 1 tablespoon of olive oil and diced onion. Cook for 10–15 minutes until soft and golden, enhancing their sweetness.

Increase the skillet's heat to medium-high, add 1 pound of ground beef, sear for 5–7 minutes without constant stirring, season with salt and black pepper, and drain excess fat once browned.

In a small bowl, combine ½ cup of mayonnaise, ¼ cup of ketchup, 1 tablespoon of mustard, and ½ teaspoon of Cajun seasoning. Whisk until smooth.

Layer crispy potatoes at the bottom of each serving bowl, followed by cooked beef, caramelized onions, shredded cheese, homemade sauce, and chopped lettuce. Add optional toppings as desired.