Step 1

Bring a large pot of water to boil and salt it. Put the oats in a food processor fitted with the metal blade and let the machine run until they’re coarsely ground into a mix of fine and coarse crumbs, about 1 minute. Transfer the oats to a bowl, add the garlic cloves to the food processor and pulse a few times to chop them. Scrape the garlic into a separate small bowl. (Now is a good time to get the cauliflower, parsley, and cheese ready to go.)

Step 2

When the water comes to a boil add the cauliflower and return the water to a steady bubble. Cook, stirring once or twice with a slotted spoon or spider until the cauliflower is easy to pierce with a fork, 10 to 15 minutes. Transfer the cauliflower to a colander with a slotted spoon or slider, leaving the cooking liquid and any remaining little bits behind. Add more water to the pot if necessary and bring it to a boil.

Step 3

Put the olive oil in a large skillet over medium heat. When it’s hot, add the oats and adjust the heat so the oat crumbs sizzle without burning. Cook, stirring frequently, until they begin to turn brown, smell toasty, and no longer taste raw, 5 to 10 minutes.

Step 4

When the oats are one shade lighter than you ultimately want them, add the garlic and keep cooking and stirring until it’s soft and turning golden, about 2 minutes. Stir in the parsley, chile, and some black pepper then transfer the crumb mixture to a serving bowl; toss in the cheese with a fork. Taste and adjust the seasoning them let the mixture sit. The oat crumbs will get crisper as they cool. Rinse out the skillet.

Step 5

Put the skillet over medium-high heat to dry then add the butter. When it foams, add the anchovies if you’re using them and mash them into the butter with a metal spatula. Add the cauliflower and about 1/2 cup cooking water from the pot. Mash and stir until a thick sauce forms, about 3 minutes. Taste and add salt and pepper if necessary; keep the sauce warm over low heat. (Have the colander handy; no need to wash it out.)

Step 6

When the pot of water returns to a boil, add the pasta. Cook, stirring occasionally, until the pasta is tender but not mushy; start checking after 5 minutes. When it’s ready, reserve about a cup of the cooking liquid and drain the noodles and add them to the cauliflower sauce. Cook, stirring and adding a little of the reserved cooking liquid until the pasta and sauce come together and are steaming hot. Taste and adjust the seasoning and serve, sprinkled with some of the oat crumbs. Pass the remaining crumbs at the table.