Sear the Sausages:

• Heat olive oil in a large skillet over medium-high heat.

• Add sausages and sear on all sides until browned.

• Transfer to a plate and set aside.

Cook the Onions:

• In the same skillet, add sliced onions and stir, scraping up any brown bits.

• Cook until softened (about 5 minutes).

• Add garlic and cook for 1 more minute.

• Season with salt and pepper.

Make the Spicy Tomato Sauce:

• Stir in tomato paste, coating the onions.

• Add diced tomatoes with chilies and bring to a boil.

• Return sausages to the skillet, cover, and reduce heat to medium-low.

• Simmer until sausages are fully cooked (about 15 minutes).

Assemble the Sandwiches:

• Warm rolls in the oven.

• Place sausages in the rolls and spoon sauce and onions over top.

• Sprinkle with grated Parmigiano-Reggiano, if desired.

Serve & Enjoy!