1. Prepare the Ingredients: Shred the cooked chicken if using whole pieces. Crumble the bacon into small bits and measure out the ranch dressing and cheese. Set aside.

2. Cook the Bacon: In a skillet over medium heat, cook the bacon until crispy. Remove it from the pan and drain excess grease on paper towels. Reserve about 1 tablespoon of bacon fat in the skillet for later use.

3. Warm the Tortillas: Place the tortilla in the same skillet (with reserved bacon fat) and warm it for about 10 seconds per side. This helps the tortilla become slightly crisp and more pliable.

4. Assemble the Filling: In a bowl, combine the shredded chicken, crumbled bacon, ranch dressing, and half of the shredded cheese. Mix gently to ensure even distribution of flavors.

5. Build the Quesadilla: Lay the warmed tortilla flat on a clean surface. Spread the chicken-bacon-ranch mixture evenly across half of the tortilla. Sprinkle the remaining cheese generously over the filling. Fold the empty half of the tortilla over the filled side, pressing down lightly to seal.

6. Cook the Quesadilla: Heat a non-stick skillet over medium heat. Place the assembled quesadilla in the skillet and cook for 3-4 minutes on each side, or until golden brown and the cheese is fully melted.

7. Serve: Slice the quesadilla into wedges using a sharp knife or pizza cutter. Garnish with optional toppings like diced tomatoes, green onions, or cilantro. Serve hot and enjoy!