Mediterranean-Style Pork on Sourdough

1 (6 to 7 pound) boneless pork loin or
1 (3 pound) pork tenderloin
2 red onions, thinly sliced
12 sourdough rolls, split
2 heads frisee
Marinade
4 cloves garlic, minced
2 tablespoons fresh rosemary, minced
2 tablespoons olive oil
1/2 teaspoon cracked black pepper
Combine marinade ingredients. Marinate pork 2 to 4 hours. Grill or roast pork until medium. Let rest 10 to 15 minutes before slicing thinly.
Tapenade
1/2 pound sun-dried tomatoes, rehydrated
3 cloves garlic
6 tablespoons olive oil
3 tablespoons Balsamic vinegar
Salt and pepper, to taste
Blend all Tapenade ingredients in food processor.
Grill or sauté onions. Spread both sides of toasted or grilled rolls with tapenade. Layer pork on bottom halves of rolls. Top with onion and frisee.