Heat 2 tablespoons olive oil in a large skillet over medium-high heat. Once shimmering, add the sausage links and cook for 5–7 minutes, turning occasionally, until browned on all sides. Transfer to a cutting board.

In the same skillet, add the Brussels sprouts (halved) and red onion (cut into wedges). Spread them in a single layer and cook undisturbed for 4–5 minutes until deeply charred on one side.

Stir the vegetables and cook for another 3–4 minutes until tender and the outer leaves are crispy and caramelized.

Slice the sausage into bite-sized pieces and return to the skillet. Add the minced garlic and red pepper flakes, toss, and cook for 1 minute until fragrant.

Deglaze the skillet with 2 tablespoons red wine vinegar, scraping up any browned bits. Season with salt and black pepper to taste. Serve hot from the pan.