Trim and halve the Brussels sprouts. Slice the yellow bell pepper into strips.
12-16 Oz. Brussels Sprouts, 1 Yellow Bell Pepper
Thinly slice one-quarter of the yellow onion into strips. Finely dice the remaining three-quarters into approximately ⅛–¼-inch pieces.
1 Very Large Yellow Onion
Heat 1–2 Tbsp olive oil in a large skillet over medium-high heat. Add the Brussels sprouts cut-side down, working in batches if necessary. Cook undisturbed for 4–6 minutes until deeply golden, then flip and cook another 3–5 minutes until tender. Season with salt and pepper, remove from the skillet, and set aside.
2-3 Tbsp Olive Oil, Salt and Fresh Cracked Black Pepper to Taste
Add the sliced sausage to the same skillet and brown over medium-high heat for approximately 5–8 minutes. During the final 4–5 minutes, add the sliced yellow bell pepper and sliced quarter-onion. Cook until the vegetables are lightly golden and the sausage is cooked through. Remove and set aside. Note: Follow package directions and verify safe internal temperatures when using raw sausage 1 Lb Fully Cooked Smoked Sausage Links
Reduce the heat to medium-low. Add the finely diced remaining onion and 2 Tbsp butter to the same pan. Caramelize for approximately 20–30 minutes, stirring occasionally, until golden, very soft, and almost jammy.
8 Tbsp Unsalted Butter
After the onions have caramelized for approximately 20 minutes, begin heating approximately 3 Qt water in a separate pot. Once boiling, salt the water (2 tsp Kosher salt or 1½ Tsp Table Salt) and add the pasta.
1 Lb Farfalle (Bowtie) Pasta
Cook the pasta according to package directions, stopping approximately 2 minutes before al dente. Continue caramelizing the onions while the pasta cooks.
When the pasta has approximately 5 minutes of cooking time remaining, add the minced garlic to the caramelized onions. Cook for 1 minute, stirring frequently.
5 Cloves Garlic
Add the balsamic vinegar, honey, (optional red pepper flakes), and a few cracks of black pepper to the onions and garlic. Stir, scraping up the browned bits, and allow the mixture to simmer gently.
1/2 C Balsamic Vinegar, 4-5 Tbsp Honey
When the pasta is approximately 2 minutes shy of al dente, reserve at least 2 C pasta water. Transfer the undercooked pasta directly into the honey-balsamic sauce, along with 1½ C reserved pasta water.
Cook over medium heat, tossing or stirring gently, until the pasta reaches al dente and the sauce begins to coat it. Add a little more pasta water if needed to maintain a generously sauced consistency.
Return the sausage and vegetables to the skillet. Gently fold everything together until warmed through.
Remove the skillet from the heat. Add the remaining 6 Tbsp cold butter, 2 Tbsp at a time, tossing or stirring thoroughly between additions until melted and incorporated. Continue until the sauce is glossy and silky.
Taste for seasonings and additional honey. Loosen with additional reserved pasta water if necessary.
Serve immediately, finished with an (optional) light drizzle of honey or the other garnishes.