Season your flank steak with garlic powder, cumin, salt, and pepper. Let it sit for a few minutes.

Heat a drizzle of olive oil in a skillet over medium-high heat. Add the steak and cook for about 4-5 minutes on each side, until cooked to your liking. Remove from the skillet and let rest.

In the same skillet, add a bit more olive oil if needed, then add the sliced bell pepper and onion. Sauté for about 3-4 minutes until tender.

Slice the rested steak thin against the grain. Place one tortilla in the skillet, sprinkle half of the cheese on one half of the tortilla. Top with a portion of sliced steak and sautéed veggies, and sprinkle with the remaining cheese. Fold the tortilla over.

Cook the quesadilla for about 3-4 minutes on each side until golden brown and the cheese has melted. Repeat with the remaining tortillas.

Slice each quesadilla into wedges and serve warm with your choice of toppings.