01 - Heat a large skillet or griddle over medium heat until hot.
02 - Place one tortilla on a clean surface. Distribute about 3/4 cup of shredded cheese blend evenly over half the tortilla. Add desired optional fillings on top of cheese. Fold tortilla in half to create a half-moon shape.
03 - Transfer folded tortilla to preheated skillet. Cook for 2-3 minutes, pressing gently with spatula, until bottom is golden brown and cheese begins to melt.
04 - Flip quesadilla carefully. Cook another 2-3 minutes until second side is golden brown and cheese is completely melted.
05 - Remove from heat and transfer to cutting board. Let rest 1 minute. Cut into 3-4 wedges. Serve immediately with sour cream, salsa, guacamole, and fresh cilantro.
06 - Repeat assembly and cooking process with remaining tortillas and filling ingredients.