Roast Fennel
Preheat oven to 450°F. Place a rimmed baking sheet in oven.
Toss fennel with olive oil and salt.
Add fennel to hot baking sheet in a single layer.
Roast until browned, 10-12 minutes.
Cook Pasta
Boil salted water. Cook pasta until al dente.
Reserve ¼ cup pasta water. Drain pasta.
Make Sauce
Heat olive oil. Cook shallots until softened, 5 minutes.
Add garlic and fennel seeds. Cook until fragrant, 1-2 minutes.
Add white wine. Cook until reduced by half, 4 minutes.
Stir in cream, lemon zest, ¼ teaspoon salt, and pepper.
Stir in reserved pasta water. Simmer until slightly thickened, 6 minutes.
Combine and Serve
Add pasta, roasted fennel, lemon juice, and red pepper flakes (if using) to sauce. Toss to combine.
Garnish with fennel fronds, pepper, and Parmesan (if using).
