Grilled Tomato And Onion Sandwich - Kentucky Living

Ingredients

• 1/3 cup olive oil
• Salt and freshly ground pepper
• 1 Tablespoon fresh rosemary, or 1 teaspoon dried
• 2 large ripe tomatoes, cut into 1/4- inch thick slices
• 2 onions, cut into 1/4-inch thick slices
• 4 large Kaiser rolls, split
• 1 bunch arugula, washed and patted dry
• 1/2 lb. fresh mozzarella, drained and thinly sliced