1. Marinate the Steak:

• In a small bowl, whisk together the olive oil, lime juice, chili powder, cumin, garlic powder, smoked paprika, onion powder, cayenne pepper (if using), salt, and pepper.

• Place the flank steak in a resealable bag or shallow dish and pour the marinade over the steak. Seal and refrigerate for at least 30 minutes, or up to 2 hours for maximum flavor.

2. Cook the Steak:

• Preheat a grill or cast-iron skillet over medium-high heat.

• Remove the steak from the marinade and cook it for 4-5 minutes per side, or until it reaches your desired level of doneness (about 130°F for medium-rare, 140°F for medium).

• Once cooked, let the steak rest for 5 minutes before slicing it thinly against the grain.

3. Sauté the Fajita Veggies:

• While the steak rests, heat 1 tablespoon of olive oil in a large skillet over medium heat.

• Add the sliced bell peppers and onions to the skillet. Season with salt and pepper, and sauté for 5-7 minutes until the vegetables are soft and slightly caramelized.

• Remove from heat and set aside.

4. Assemble the Quesadillas:

• Place a tortilla in a clean skillet over medium heat.

• Sprinkle a small amount of cheese on one half of the tortilla, then layer with a few slices of the grilled steak, sautéed bell peppers and onions, and more cheese.

• Fold the tortilla in half to create a half-moon shape.

5. Cook the Quesadillas:

• Add 1 tablespoon of butter to the skillet. Once melted, place the folded quesadilla into the skillet and cook for 3-4 minutes per side, or until golden brown and crispy, and the cheese has melted.

• Repeat with the remaining tortillas.

6. Serve:

• Once cooked, slice the quesadillas into wedges and serve with sour cream, guacamole, or salsa on the side.