Heat a skillet over medium-high heat and add the vegetable oil. Once shimmering, add the ground beef, breaking it apart with a spatula. Cook until browned and cooked through, about 5-7 minutes. Drain excess fat if necessary.
Add cumin, chili powder, salt, and black pepper to the cooked beef. Stir well and cook for 1-2 more minutes until fragrant. Remove from heat and set aside.
Grate the cheese and set aside. Prepare the tortillas by laying them flat on a clean surface.
Spread a quarter of the seasoned beef evenly over half of a tortilla, then sprinkle with a quarter of the cheese. Fold the tortilla in half to enclose the filling, creating a half-moon shape.
Place one assembled quesadilla into the hot skillet. Cook for 2-3 minutes until the underside is golden brown and crispy, then flip using a spatula and cook the other side until equally crispy and the cheese has melted.
Remove the cooked quesadilla from the skillet and let it rest for 1 minute. Slice into wedges with a sharp knife and serve warm.
