Heat oven to 400ºF.

Bring a large pot of salted water to a boil and cook the pasta according to the directions on the package, until it's al dente. Drain.

Meanwhile, toss the Brussels sprouts and fennel in olive oil and spread on a baking sheet in a single layer. Bake 10 minutes, turning once, or until they begin to brown.

Melt the butter in a saucepan set over medium heat. Whisk in the flour and cook for 1 minute. Slowly whisk in the cream and broth. Bring to a simmer and let cook 5-7 minutes, or until thick and creamy.

Combine the cooked pasta with sauce, cauliflower, Brussels sprouts, fennel, and goat cheese. Spread in an 8-inch square baking pan. Top with breadcrumbs and bake for 10 minutes, or until crisp and golden brown.

Drizzle with balsamic reduction just before serving.