Chef Scott Conant makes creamy asparagus soup and a panini with mortadella, pickled red onion, and aged provolone.
Heat a panini grill to hot or a grill pan to medium.
Place slices of mortadella on one of the slices of ciabatta. Add onions and cheese; top with remaining slice of ciabatta.
Brush top and bottom of the sandwich with olive oil. Place in panini grill and press until bread is crisp and brown, and cheese has melted slightly, 9 to 10 minutes. If using a grill pan, press sandwich down with a heavy pan set on top of the sandwich, cooking, turning once, 2 to 3 minutes per side. Cut sandwich in half and serve immediately.