Preparation:

1. Preheat oven to 400°F. Line a sheet pan with foil and set aside.
2. Place a large cast-iron skillet over medium-high heat. When hot, add 2 tablespoons of olive oil. When oil is shimmering, add pork tenderloin to the pan and sear on all sides, about 2 minutes per side.
3. Transfer pork to a sheet pan and place in the oven. Roast for 25 to 30 minutes, or until the internal temperature reaches 145°F.
4. In the same skillet used to brown the pork, heat remaining tablespoon olive oil over medium heat. Add garlic, red pepper flakes, and kale. Cook until kale is wilted. Stir in red wine vinegar, season to taste with salt and pepper, and set aside.
5. When pork is cooked, remove from the oven and let rest for 10 minutes before slicing thin.
6. Spread mayonnaise and mustard liberally on cut sides of rolls. Add sliced pork, cooked greens, and 2 slices of cheese to each roll. Place sandwiches back on the sheet pan and return to the oven for 5 minutes, or until the cheese is melted.
7. Remove sandwiches from the oven and serve immediately.