MOST OF THE TIME, LEFTOVER INGREDIENTS JUST DON'T muster up the same enthusiasm as they did their first time around. But when artfully arranged in little panini rolls, leftovers take on a whole new excitement. These mini-sandwiches are the answer to using up all of those odds and ends you've accumulated after sandwich night at your house. Those few tablespoons of aioli or pesto, the six stray olives, those bits and pieces of roasted red pepper, and that half-ball of mozzarella will no longer hang around in your refrigerator, waiting to be thrown away the following week.
These sandwiches are pretty to look at, easy to put together, and, thank goodness, don't warrant a recipe. Start out with 2Þ-inch crusty white rolls. To duplicate the flatter, Italian-style focaccete, you may have to slice a Þ inch or so from the center of your bread. To do this, use a serrated knife to cut the roll in half horizontally, and then trim each half accordingly.
Remember, these are minimal, three-bite snacks, so stick to simple flavor combinations and don't overstuff them with complicated ingredients. Depending on what you have lying around, you can make one type or an assortment of sandwiches. Just make sure the bread is moistened with a leftover condiment, such as aioli, salsa romesco or basil pesto. If you don't have any homemade condiments left, improvise by smearing the bread with softened butter or a drizzle of extra-virgin olive oil.
To show off what's inside, layer your ingredients with care and consideration. Rumple a scrap of prosciutto, exposing its curled edge as it leans against the cross section of a sliced black olive. Combine that remnant of salmon with cucumber slices and hard-cooked egg, stacking the layers unevenly to reveal the colorful fillings. You may want to accent them with a sprig of dill, a fennel-frond sprig or a tiny basil leaf.
Close your eyes. Take a bite. You might just think you're standing at the bar at Café Greco in Rome.