Preheat oven to 400°F.
Line a sheet pan with parchment paper.
Toss cauliflower with salt, pepper, and 3 tbsp olive oil. Place the cauliflower in a single layer on the prepared sheet pan and roast in preheated oven until golden brown, about 25 minutes, tossing halfway through.
In the meantime, bring a large pot of salted water to a boil. Cook pasta 1 minute less than the package instructions so it is al dente. Reserve 1 cup cooking water.
Drain the pasta and set aside.
When the cauliflower is done, heat remaining 2 tbsp olive oil over medium-high heat in the same pot that you cooked the pasta.
Add capers, and cook until crispy, about 2-3 minutes. Remove capers with a slotted spoon, and set aside.
Reduce heat to medium, add garlic, anchovy paste, and crushed red pepper. Cook, stirring often until garlic is lightly golden, about 1 to 2 minutes.
Add pasta, lemon zest,1 cup reserved cooking water and 2 tbsp cheese. Toss to coat until shiny. Add the roasted cauliflower and toss again.
Remove from heat and garnish with crispy capers, remaining 2 tablespoons cheese, and parsley.
