Season the Steak: In a small bowl, mix together the garlic powder, onion powder, smoked paprika, salt, and black pepper. Rub this seasoning mixture all over the steak.

Cook the Steak: Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the steak and cook for 4-5 minutes per side, or until it reaches your desired level of doneness. Remove the steak from the skillet and let it rest for 5 minutes before slicing it thinly against the grain.

Sauté the Vegetables: In the same skillet, add the sliced onion and bell pepper. Sauté for 4-5 minutes, or until the vegetables are softened and slightly caramelized. Remove from heat.

Assemble the Quesadillas: Lay one flour tortilla on a flat surface. Sprinkle 1/2 cup of shredded cheese over half of the tortilla. Add a portion of the sliced steak, sautéed onions, and bell peppers on top of the cheese. Fold the tortilla over to create a half-moon shape. Repeat with the remaining tortillas and fillings.

Cook the Quesadillas: Wipe out the skillet and return it to medium heat. Place one quesadilla in the skillet and cook for 2-3 minutes on each side, or until the tortilla is golden brown and the cheese is melted. Repeat with the remaining quesadillas.

Serve: Slice the quesadillas into wedges and serve with sour cream, salsa or pico de gallo, chopped fresh cilantro, avocado slices, and crumbled queso fresco or feta cheese if desired.