Preheat oven to 350°F. Trim fat from pork. Using a sharp knife, make a lengthwise cut down the center of the loin, cutting to, but not through, the opposite side. Cut horizontally into the meat, slicing away from the center cut and cutting to, but not through, the opposite side. Repeat on the opposite side. Open so pork is flat. Place plastic wrap over pork. Using the flat side of a meat mallet, pound to an even thickness.
In a small bowl, combine roasted sweet peppers, parsley, olives, lemon peel, garlic and thyme. Spread pepper mixture to an even layer over the roast. Roll the roast into a spiral. Tie roast with 100-percent-cotton kitchen string. Place roast, seam side down, on a rack in a shallow roasting pan. Sprinkle meat with the salt and pepper.
Roast, uncovered, for 50 to 60 minutes or until an instant-read thermometer inserted into center of roast registers 145°F. Remove from oven. Cover meat with foil and let stand for 3 minutes. Remove string before slicing. If desired, serve with Chorizo Custard Dressing (see associated recipe).
135 calories;4 g fat(1 g sat); 0 g fiber; 1 g carbohydrates; 22 g protein; 3 mcg folate; 60 mg cholesterol; 0 g sugars; 0 g added sugars; 170 IU vitamin A; 21 mg vitamin C; 13 mg calcium; 1 mg iron; 183 mg sodium; 317 mg potassium