Step 1: Heat oil in a large skillet on medium heat. Cook onions for 5 minutes. Stir in garlic, and cook for 30 seconds. Cook ground beef until it is no longer pink. Drain excess fat.
Step 2: Incorporate ketchup and brown sugar. Season generously with chili powder. Allow to simmer for 5 minutes. Transfer the mixture to a plate.
Step 3: Add a flour tortilla to the skillet over medium heat. Sprinkle with the ground beef mixture and then top with cheese and Monterey Jack. Top with a second tortilla. Cook the tortilla until it is golden brown, approximately 2 minutes. Then flip the tortilla and cook for 2 minutes more.
Step 4: Repeat the steps with all remaining ingredients. Cut into wedges and heat.