Step 1

Bring a large pot of salted water to a boil.

Step 2

Meanwhile, heat the olive oil in a large Dutch oven over medium-high heat. Add the cauliflower and a couple of generous pinches of salt and cook, stirring every so often, until the cauliflower is well-browned and soft, 10 to 12 minutes. Add the chile flakes, garlic and lemon zest and cook for 1 minute. Remove the pot from the heat while you cook the pasta.

Step 3

Cook the pasta al dente, according to package directions, and reserve 1 cup of the cooking water before draining.

Step 4

Return the Dutch oven to medium-high heat and add the drained penne and 2/3 cup of the reserved cooking water. Cook for another minute, stirring everything together, and adding a little more cooking water if the pasta looks dry.

Step 5

Remove the pot from the heat, season to taste with more salt, and stir in the chopped parsley. Serve the pasta in bowls with lots of grated Parmesan and freshly ground black pepper showered on top.