1. Heat the olive oil in a large skillet over medium-high heat. Add the sliced steak, cooking until browned and just cooked through. Remove from skillet and set aside.
2. In the same skillet, add the bell peppers and onion. Sauté until they are softened and beginning to caramelize, about 5-7 minutes. Season with salt and pepper.
3. Return the steak to the skillet, mixing it with the peppers and onions until everything is well combined. Remove from heat.
4. On a separate clean surface, lay out the flour tortillas. Place a slice of provolone cheese on one half of each tortilla, then evenly distribute the steak and vegetable mixture over the cheese.
5. Fold the tortillas in half, pressing down gently to hold the filling in place.
6. In a clean skillet, melt 1 tablespoon of butter over medium heat. Cook each quesadilla for about 3 minutes per side, or until the tortillas are golden brown and the cheese has melted. Add more butter to the skillet as needed.
7. Remove from skillet, slice into wedges, and serve warm.

Pro tip: Use your senses just like my abuela taught me—listen for the sizzle, smell the savory aroma, and you’ll know when your quesadillas are just right!