Thinly slice your onion.
1 large yellow onion
Heat up a pot over medium heat then add butter.
1 tbsp butter
Add your thinly sliced onions and continue stirring until caramelized. This will take roughly 30-40 minutes over med-low heat and if it starts to burn you can add a splash of water to deglaze the pan.
Give your shallot and celery a really fine dice.
½ shallot, ½ stalk celery
Drain your can of tuna and place into a bowl.
1 can tuna
Mix in mayo, celery, shallots, lemon juice, and black pepper
⅓ cup mayo, ½ shallot, 1 tsp lemon juice, ½ tsp black pepper, ½ stalk celery
Place your slices of cheese on top of the bread.
2 slices Italian bread, 3 slices monterey jack cheese
Add tuna, top with caramelized onions, and cover with top bun.
Spread garlic butter on both sides of the bread then air fry at 400F for 10 minutes flipping halfway through.
garlic butter