01 - Heat olive oil in a large skillet over medium heat. Add chopped onion and diced red bell pepper; sauté for 2 to 3 minutes until softened.
02 - Stir in minced garlic and cook for 30 seconds until fragrant.
03 - Add ground beef, breaking it up with a spoon, and cook for 5 to 7 minutes until browned and fully cooked. Drain excess fat if necessary.
04 - Incorporate ground cumin, chili powder, smoked paprika, salt, and black pepper. Cook another 2 minutes while stirring. Remove from heat and set aside.
05 - Heat a clean large skillet or griddle over medium heat.
06 - Place one tortilla on the skillet. Evenly sprinkle with 1/4 cup cheddar and 1/4 cup Monterey Jack cheese, then spread about 1/4 of the beef mixture over the cheese. Add cilantro if desired.
07 - Top with a second tortilla. Cook 2 to 3 minutes until the bottom is golden and cheese begins to melt. Carefully flip and cook another 2 minutes until golden and crispy.
08 - Repeat the assembly and cooking process with remaining tortillas and filling.
09 - Slice quesadillas into wedges and serve immediately with sour cream, salsa, and guacamole as desired.