Caramelized Onion & Fennel Pasta

Steps

1. Trim the fennel by removing the tough root end and stalks. Pick off the fennel fronds and reserve for garnish. Thinly slice the fennel, onion, and garlic. Chop the capers.
2. Heat the olive oil in a large skillet over medium heat. Add the sausage and cook until browned and cooked through. Remove the sausage and discard the rendered fat.
3. Add the butter and Calabrian chili to the skillet. Stir in the onion, fennel, garlic, and a pinch of salt. Pour in the white wine (or sparkling water) and cook, stirring occasionally, until the vegetables are deeply browned and soft. Taste the fennel to make sure it is fully tender.
4. Meanwhile, cook the spaghetti in well-salted water until just shy of al dente. Reserve plenty of pasta water.
5. Add the spaghetti directly to the skillet with the vegetables. Add pasta water in ¼-cup increments, tossing constantly until the liquid emulsifies into a glossy sauce.
6. Stir in the Parmesan, cooked sausage, and a little more pasta water if needed, continuing to toss until creamy and emulsified.
7. Fold in the chopped capers and finish with the lemon juice or red wine vinegar. Taste and adjust the seasoning.
8. Serve with additional Parmesan and garnish with the reserved fennel fronds.