2 jalapeños, seeded, if desired, and thinly sliced
8 ounces shredded Mexican-blend cheese
6 (8-inch) flour tortillas
Directions
Cut the skirt steak to fit the skillet, if needed, and pat dry. Sprinkle the steak on both sides with chili powder, ½ teaspoon salt, and ¼ teaspoon black pepper, coating the steak evenly.
Heat a skillet over medium heat, then add 1 tablespoon oil and heat until shimmering.
Transfer the steaks to the hot skillet and sear until browned, 3 to 4 minutes.
Flip and cook on the other side until the steaks reach your desired doneness (130 F for medium-rare).
Transfer the steaks to a cutting board and rest for 10 minutes.
In the meantime, add 1 tablespoon oil, the onions, and the remaining ¼ teaspoon salt and ¼ teaspoon pepper to the skillet over medium heat.
Cook for about 5 minutes, stirring occasionally, until the onions are translucent.
Add the jalapeños and cook for an additional 2 to 3 minutes, stirring occasionally, until lightly browned.
Transfer to a small bowl and set aside. Wipe the skillet clean.
Use a sharp knife to slice the steak across the grain into roughly ¼ inch–thick slices.
Lay out one tortilla.
Top evenly with a layer of cheese.
Top with ⅓ of the steak.
Top with ⅓ of the onion mixture.
Top with another layer of cheese, and finish with a tortilla. Repeat with the remaining tortillas, cheese, steak, and onion mixture to make 3 quesadillas total.
Heat 1 teaspoon oil in a skillet over medium-low heat.
Add one quesadilla to the pan and cook for 2 to 3 minutes on the first side, until browned.
Flip and cook the remaining side until browned and heated through.
Transfer to a serving plate or cutting board and repeat with the remaining quesadillas.
Cut the quesadillas into sections and serve hot, with your desired toppings.