Prepare Filling: Drain and rinse a can of black beans, then place them in a mixing bowl. Dice one ripe avocado and add it to the beans. Squeeze fresh lime juice and mix together until well combined.

Assemble Quesadilla: Lay a tortilla flat, spoon the avocado and black bean mixture onto one half, sprinkle cheese, and fold the tortilla over the filling.

Cook: Heat a non-stick skillet over medium heat with olive oil or butter. Cook the folded quesadilla for 2-3 minutes until golden brown, then flip and cook the other side.

Serve Immediately: Cut the quesadilla into wedges and serve warm with fresh salsa or guacamole.