Begin by gathering all your ingredients for the Smashburger Quesadillas. Chop the onion and any additional toppings like bell peppers or jalapeños, aiming for bite-sized pieces.

In a large skillet over medium heat, add a splash of oil and let it heat up. Once ready, add the ground beef, cooking it until it reaches an internal temperature of 160°F, approximately 6-8 minutes. Drain any excess fat before stirring in taco seasoning.

Take a tortilla and lay it flat. On half of the tortilla, layer the cooked beef, cheese, and any additional toppings. Fold the tortilla over to create a half-moon shape.

Return the skillet to the heat, adding more oil if necessary. Place the assembled quesadilla into the skillet. Cook for about 3-4 minutes until the bottom is golden brown, then flip and cook the other side.

Once both sides are golden, remove from skillet and allow to cool slightly before slicing into wedges. Serve hot with salsa and guacamole.