Heat a skillet over a moderately high heat.
Dry the steak with paper towels.
Combine the onion powder, garlic powder, salt, pepper, and cumin, and rub this into the steak.
Add 1½ tablespoons of oil to the skillet and cook the meat in there for about 6 minutes per side.
Let the steak rest on a cutting board.
Add ½ tablespoon more oil to the skillet and cook the onions for about 8 minutes or until tender.
Transfer the cooked onions into a bowl and wipe out the skillet with paper towels.
Cut the steak against the grain into chunks or slices.
Combine the cheeses.
Add ½ cup of cheese to a tortilla and then some steak and onions and another ½ cup of cheese.
Add a little salt and then another tortilla on top.
Using a spatula, put the quesadilla into the skillet and cook for 1 or 2 minutes until golden brown underneath.
Flip and cook for another minute or 2 on the other side.
Repeat with the rest of the quesadillas and serve immediately.
Enjoy!