1/3 cup olive oil
salt and freshly ground
pepper
1 tablespoon fresh rosemary or 1 teaspoon dried rosemary
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 pound fresh Mozzarella, drained and thinly sliced

Preheat grill or broiler to a medium heat. Combine the olive oil with salt, freshly ground pepper and rosemary. Brush the olive oil mixture over each tomato slice, onion slice and half roll. Grill or broil the onion slices until they are tender and blackened, about 10 minutes. Briefly grill or broil the tomato slices until they are warm. Do not overcook them. Grill or broil the rolls on one side until golden brown. Transfer all to a warm platter. Assemble the sandwiches by layering the arugula, tomatoes, onions and Mozzarella on the bottom half of the roll. Top with the second half of the bun. Cut in half and serve.