Preheat the oven to 425°F. Bring a large pot of salted water to a boil. In a 9x13-inch baking dish, toss the broccoli with 2-3 tablespoons of olive oil and push to one side. Place the cream cheese in the center (if using). Pat the salmon dry, place it on the other side, and drizzle with the remaining olive oil. Sprinkle everything with Italian seasoning and garlic, tossing the garlic with the broccoli. Season with salt and pepper.

Bake for 15-17 minutes, until the salmon is cooked through and the broccoli is tender with crispy edges. Meanwhile, cook the pasta according to package directions. Reserve at least 1 cup of pasta water before draining.

Remove the salmon from the dish and set aside. Pour in 1/2 cup of the reserved pasta water and stir the broccoli, cream cheese (if used), and pasta together until well combined. Tear in the mozzarella pieces and stir until melted. If needed, return the dish to the oven for 2-3 minutes to melt.

Add more pasta water if needed for a creamy texture. Taste and adjust seasoning. Break the salmon into bite-sized pieces and sprinkle over the pasta. Serve warm.