Heat oil in a large pan over medium heat. Add onion and cook until tender; about 3 minutes. Add tomato and stir, cook for 5 minutes or until tomato pieces break apart. Add potatoes and season with garlic salt.

Add eggs and fold all ingredients until egg sets. Remove from heat and set aside.

Preheat waffle iron to medium heat. Spray waffle plates with non-stick cooking spray. Place a flour tortilla on the waffle plate, place a few pieces of cheese and 3-4 tablespoons potato and egg mixture cover with another flour tortilla and close waffle iron. Cook for 3-5 minutes or until tortilla begins to brown. Repeat with remaining ingredients.

Transfer waffle quesadillas to a cutting board, slice into fourths. Serve with a side of sour cream and avocado slices. Sprinkle with fresh cilantro and crumbled cotija cheese.