Spread Pine Nut Pesto onto baguette slices, and top with shaved Parmesan and tomato.
If desired, top with basil and nuts.
Combine 1 cup firmly packed fresh basil; 1 cup torn fresh arugula or spinach, ¼ cup grated Parmesan or Romano cheese; ¼ cup pine nuts, chopped walnuts, or chopped almonds, toasted; 1 tablespoons olive oil; 1 tablespoon white balsamic vinegar; 1 clove garlic , quartered; and ¼ teaspoon salt in a small food processor.
Cover and process with several on-off turns until a paste forms, stopping several times to scrape the side.
Process in enough water, adding 1 tablespoon water at a time, until the pesto reaches the consistency of soft butter.