Smoked sun-dried tomatoes give this sandwich a meaty taste and texture.
1. Layer avocado slices, tomatoes, onion, and ½ cup spinach on each roll. Spray panini with cooking spray.
2. Coat skillet or grill pan with cooking spray, and heat over medium heat. Place panini in pan; weight with smaller-diameter saucepan weighted with 1 or 2 cans. Cook 2 minutes, remove weight, flip panini, replace weight, and cook 1½ to 2 minutes more. (Or cook 4 minutes in panini maker.)