01 - Heat a large skillet or griddle over medium heat until evenly hot.
02 - Place one tortilla on a clean surface. Distribute approximately 3/4 cup of the shredded cheese blend evenly over half the tortilla. Layer with desired optional fillings. Fold the tortilla in half to form a half-moon shape.
03 - Transfer the filled tortilla to the preheated skillet. Cook for 2 to 3 minutes, pressing gently with a spatula, until the bottom develops a golden-brown crust and the cheese begins to melt.
04 - Carefully flip the quesadilla and cook the second side for an additional 2 to 3 minutes until golden brown and the cheese is completely melted.
05 - Remove from skillet and transfer to a cutting board. Allow to rest for 1 minute, then cut into 3 to 4 wedges. Serve immediately with sour cream, salsa, guacamole, and fresh cilantro.
06 - Repeat the assembly and cooking process with the remaining tortillas and filling ingredients.