Place sausages in a skillet and add enough water to come halfway up the sides of the links. Drizzle EVOO over them and place on stove over high heat; bring to boil then reduce heat to medium. Cook to evaporate the liquid, and brown and crisp the casings.
Meanwhile, bring a large pot of water to a boil for the pasta.
In a medium pot or deep skillet, heat EVOO, a turn of the pan, with butter. When butter melts into oil, add fennel, fronds, onions and garlic; season with salt and pepper to taste and stir to soften 10-12 minutes. Sprinkle flour over the fennel and stir a minute then add wine and deglaze the pan. Stir in stock and milk, and cook to thicken, 5-7 minutes.
Cook macaroni to al dente.