Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
Lay the sausage pieces in the center of the sheet pan, and scatter the sliced red and yellow bell peppers and onions around them.
Drizzle the sausage and veggies with olive oil and red wine vinegar, then sprinkle on the minced garlic, kosher salt, dried basil, oregano, black pepper, and red pepper flakes.
Toss everything together to ensure it’s evenly coated, then spread the mixture in a single layer on the sheet pan.
Roast for 25-35 minutes, stirring halfway through, until the vegetables are tender and caramelized.
(Optional) Garnish with fresh basil, chopped parsley, or a sprinkle of Parmesan cheese before serving.