Preheat oven to 450 degrees.
Combine garlic, rosemary, lemon peel, salt and pepper. Press mixture into tenderloins.
In large skillet with oven-proof handle, heat oil over medium heat. Add tenderloins and cook, turning frequently, until browned 8 – 10 minutes.
Transfer to oven. Roast 10 minutes. Remove pork from pan and keep warm. Set pan over high heat and stir in broth and vinegar, scraping up browned bits. Bring to boil and cook until reduced by 1/3 to ½. Whisk in butter, 1 Tbsp. at a time. Stir in capers.
Cut tenderloins into thick slices and serve with sauce.