Lightly coat an unheated panini griddle, covered indoor electric grill, or large nonstick skillet with cooking spray; set aside.Advertisement
Place 4 of the bread slices or 4 pita pieces on a work surface; divide half of the spinach leaves among bread slices or pita pieces. Top spinach with tomato slices. Sprinkle with pepper. Add red onion slices and basil. Top with feta and remaining spinach. Top with remaining bread slices or pita pieces. Press down firmly.
Preheat griddle, grill, or skillet over medium heat or heat according to manufacturer's directions. Add sandwiches, in batches if necessary. If using griddle or grill, close lid and grill for 2 to 3 minutes or until bread is toasted. (If using skillet, place a heavy plate on top of sandwiches. Cook for 1 to 2 minutes or until bottoms are toasted. Carefully remove plate, which may be hot. Turn sandwiches and top with the plate. Cook for 1 to 2 minutes more or until bread is toasted.)
1 1/2 starch, 1 1/2 vegetable, 1/2 medium-fat protein