Mix the tuna, mayonnaise, onion, red onion, and habanero together.
Put cheese on each tortilla, top with half of the tuna mixture, cheese, and the remaining tortilla.
Heat a cast iron pan on low then melt the butter in a pan.
Put the quesadilla in the pan. Depending on the size of your pan, you might have to do this in batches. Cook on one side on low heat until the cheese melts, about 3 minutes.
Turn and cook on the other side.
Serve with sliced avocado, sour cream, and Tabasco.
Notes
If you don't like spicy foods, omit hot sauces.
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