Pasta with Sausage and Broccoli Rabe

hot Italian sausage, casing removed

Kosher salt and ground black pepper

orecchiette pasta

extra virgin olive oil, divided, plus more to serve

medium garlic cloves, smashed and peeled

fennel seeds, crushed

red pepper flakes

Parmesan cheese, grated (1/2 cup), plus more to serve

broccoli rabe, trimmed and finely chopped (about 8 cups)