Heat a medium to large size pan on medium high heat with a little bit of cooking spray (or a tiny bit of oil). I usually use an extra virgin olive oil cooking spray.
Then, toss your tortilla into the pan. I use these organic flour tortillas that need to be cooked on each side for 15-30 seconds.
If you're using regular tortillas, put a tortilla in the pan and then flip it over after 10-15 seconds, just to heat it up on both sides and start getting a little bit of crispiness.
Working quickly, add your shredded cheese, directly onto one side of the tortilla in the pan. Only fill one side of the tortilla with cheese because eventually, you'll be flipping the other half on top to make a half moon shape.
Next, add your black beans.
Then, add minced onion and jalapeño evenly on top of the cheese. Add a sprinkle more of shredded cheese if desired. I usually don't do this.
Then, fold the empty half of the tortilla over all the toppings and flatten / push down the top a little bit with a spatula.
Once you can see the cheese starting to melt (1-2 minutes), flip the quesadilla over in the pan.
Remove from heat after another 1-2 minutes. Slice into 4 pieces and serve with sour cream, shredded lettuce, salsa, or even guacamole. Most of the time, I only have sour cream in the fridge. But when I'm feeling fancy, I'll add a bunch of shredded lettuce and some guacamole to make it even more filling.