In a medium nonstick skillet, heat 2 tablespoons of oil over medium heat.

Add the onion and cook, stirring, until softened, 3 to 4 minutes.

Add the beef, breaking it up into bits, and cook, stirring, until it starts to brown, 4 to 5 minutes.

Add oregano, cumin, and crushed red pepper.

Stir to mix with the meat.

Add the tomatoes and cook until the juices reduce and the mixture is nearly dry, about 5 minutes.

Season with salt.

Heat a large dry nonstick skillet over medium heat, and warm the tortillas, one at a time, turning once or twice, until soft and limp, about 20 seconds.

Wrap in a clean kitchen towel to keep moist and soft.

(This prevents the tortilla from cracking when it’s folded.

) Put 1 tortilla on a flat work surface.

Spread ⅓ cup of the meat mixture half the tortilla and top with ⅓ cup cheese.

Fold in half.

Press lightly to flatten and put on a baking sheet.

Cover with a piece of plastic wrap to prevent drying out.

Repeat with the remaining tortillas and fillings.

(Can be made ahead to this point, covered with plastic wrap and refrigerated up to 3 to 4 hours before frying.

)

Preheat oven to 200°.

In a large nonstick skillet, heat about 2 tablespoons oil over medium heat until it starts to shimmer.

Put 1 quesadilla in the skillet and fry, turning once, until golden brown on both sides and the cheese is melted, about 1 to 2 minutes on each side.

Drain on paper towels.

Keep warm in the oven.

Repeat until all are fried.