Preheat oven to 400°F.
Heat 2 tablespoons extra virgin olive oil in large, oven-safe sauté pan over medium heat. Add sausages and brown on all sides. Remove sausages to plate and return pan to stove. Add onions, peppers, and mushrooms. Sauté 5 minutes.
Cut sausages in half lengthwise and place in pan with vegetables. Place pan in oven and bake 15 minutes. Remove from oven.
Preheat panini grill over medium-high heat. Drizzle buns with olive oil and halve. Place 1 ounce (generous 1/8 cup) grated Asiago cheese on each roll bottom; top with 1 slice Fresh Mozzarella. Layer with 2 sausage halves and approximately 1/2 cup of the onions-peppers-mushrooms. Drizzle with a few drops of white or black truffle oil, if using. (A little goes a long way.) Top with 1/4 cup pepper strips, additional slice Fresh Mozzarella, and ciabatta tops. Place in panini press for 5 minutes or until cheese melts and bread is golden brown.
- 6 tablespoons extra virgin olive oil, divided
- 4 sweet Italian sausages
- 2 onions, such as Vidalia, sliced 1/4" thick
- 1 large bell pepper, sliced 1/4" thick
- 4 ounces cremini or button mushrooms, sliced 1/4" thick
- 4 ciabatta rolls
- 4 ounces Wisconsin Asiago cheese, grated
- 8 1/8" thick slices Wisconsin Fresh Mozzarella cheese
- White or black truffle oil, optional
- 1 cup jarred, roasted red pepper strips