In a large bowl, toss the sliced onions and bell peppers with half of the fajita seasoning and a tablespoon of olive oil until everything’s coated and glossy.

Heat a large cast-iron skillet over medium-high heat and add the veggies. Cook for about 10–12 minutes, stirring occasionally, until they’re soft, a little charred, and smell amazing. Transfer them to a plate and set aside.

In the same bowl (because we’re not dirtying more dishes than we have to), toss the sliced chicken with the remaining seasoning and another tablespoon of oil.

Add the chicken to the hot skillet and cook for 6–8 minutes, flipping halfway through, until golden and cooked through.

Return the peppers and onions to the skillet, squeeze in a little lime juice, and give everything a good stir so the flavors come together. Remove from heat.

Lay a tortilla flat and spoon about ¼ of the fajita filling over one half. Sprinkle generously with shredded cheese, then fold it over to close.

Heat a clean skillet or griddle over medium heat and melt about ½ tablespoon of butter.

Add your quesadilla and cook until golden and crisp, about 2–3 minutes per side. Repeat with the rest, adding more butter as needed (because butter makes everything better).

Slice into halves, sprinkle with fresh cilantro, and serve warm — melty, cheesy perfection.