Prosciutto, Mozzarella, and Arugula Panini

Ingredients

• 4 teaspoons balsamic vinegar
• 2 teaspoons extravirgin olive oil
• 1/4 teaspoon black pepper
• 1 garlic clove, minced
• 1 (9-ounce) loaf ciabatta, cut in half horizontally
• 16 very thin slices prosciutto (about 4 ounces)
• 4 (1-ounce) slices part-skim mozzarella cheese
• 8 (1/4-inch-thick) slices tomato (1 medium tomato)
• 1 cup lightly packed trimmed arugula or spinach
• Olive oil-flavored cooking spray

Preparation

1. 1. Combine first 4 ingredients in a small bowl; stir well with a whisk.
2. 2. Brush cut sides of bread with vinaigrette. Arrange prosciutto and next 3 ingredients over bottom half of bread; replace top half of bread. Cut loaf in half crosswise, and coat with cooking spray.
3. 3. Heat a large grill pan or nonstick skillet over medium heat. Add sandwich halves to pan. Place a heavy skillet on top of sandwiches to weigh them down. Cook 3 minutes on each side or until bread is toasted and cheese melts. Cut each sandwich half in half again to form 4 equal portions. Serve immediately.
4. Note: Focaccia may be substituted for ciabatta.
5. Panini (pah-NEE-nee) translates as "rolls" or "little bread," but in Italy, the name is synonymous with sandwiches.