Preheat the oven to 450 degrees and line a baking sheet with parchment paper.
Add the cauliflower ingredients to the baking sheet and toss to coat evenly. Place in the oven and bake for 25-30 minutes, flipping halfway and cooking until crispy.
Add the bread crumb ingredients to another baking sheet and toss to combine. Place in the oven with the cauliflower and cook until browned (2-3 minutes). Remove from the oven and transfer to a bowl.
While the cauliflower is cooking, bring a large pot of water to a boil. Add salt to the water before adding the pasta. Cook the pasta according to package instructions and drain.
Place the empty pot back on the stove over medium heat. Add the butter, garlic, shallot, a pinch of salt & pepper and the rosemary to the pot. Cook, stirring frequently, for 2-3 minutes. Add the milk, broth and flour. Whisk until smooth and bring to a boil.
Lower heat and add parmesan and cream cheese. Whisk until smooth and allow to cook until slightly thickened. Turn the heat off.
Add the basil, parsley and lemon juice to the sauce and stir to combine. Add the pasta and toss until coated.
Serve pasta with the garlic bread crumbs, cauliflower, additional parsley and red pepper flakes.