Step 1

Preheat oven to 400°F. Prick Italian sausages all over using a knife. Place sausages in a cold large ovenproof skillet. Cook over medium-high, flipping occasionally, until browned on all sides, about 14 minutes. Transfer to a plate. Do not wipe skillet clean.

Step 2

Add bell peppers and onion to skillet; cook over medium-high, stirring often, until softened, about 6 minutes. Add tomato paste, garlic, salt, and crushed red pepper; cook, stirring often, until vegetables are well coated in tomato paste and garlic is tender and aromatic, about 2 minutes. Stir in broth and vinegar. Bring to a boil over medium-high. Boil, stirring often, until liquid has almost completely reduced, about 6 minutes. Return sausages to skillet.

Step 3

Transfer skillet to preheated oven, and roast until vegetables are tender and a thermometer inserted in thickest portion of sausages registers 160°F, about 15 minutes. Remove from oven; let stand until cool enough to handle, 3 to 5 minutes. Serve with crusty bread.