Prepare a rimmed baking sheet with either parchment paper or foil and place a baking rack inside. Set aside.
Place the ground beef, finely diced onion, salt, pepper, and Dijon mustard in a large bowl and mix until thoroughly combined.
Fold each tortilla in half and open again. The fold line will be your guide. Place one slice of cheese on the bottom half of the tortilla (below the fold).
Press a thin and even layer of the ground beef mixture over the bottom half of the tortilla (on top of the cheese) working the meat to evenly cover and follow the lines of the tortilla. The ground beef should be approximately ¼" thickness.
Add another slice of cheese on top of the meat mixture and fold the empty side of the tortilla over the meat and cheese. Continue the same process with the remaining ingredients.
Brush a light coating of oil on the top and bottom of each tortilla-wrapped burger and sprinkle with sesame seeds if desired.
Bake in the preheated oven for 15 minutes or until lightly golden and crispy. Remove. Cool slightly, and serve.
Video
Notes
Store any leftovers in an airtight container in the refrigerator for up to 5 days.May be frozen after cooking. Wrap each burgerdilla individually in freezer paper or plastic wrap and store in a zip top freezer bag for up to 2 months.Reheat (uncovered) in an oven or air fryer for crispiness.