Step 1

Arrange a rack in the middle of the oven and heat the oven to 400°F.

Step 2

Peel off and discard the excess papery skins from 1 medium head of the garlic, then slice a thin layer off the top to expose the cloves. Place cut-side up on a piece of aluminum foil. Drizzle with 1 teaspoon of the olive oil and sprinkle with a pinch of kosher salt. Wrap the garlic completely in the foil.

Step 3

Roast until the garlic is tender and caramelized, 45 to 50 minutes. Meanwhile, thinly slice the remaining 4 garlic cloves. Coarsely chop 1/3 cup loosely packed fresh parsley leaves.

Step 4

About 20 minutes before the garlic is ready, bring a large pot of salted water to a boil. Add 1 pound dried bucatini pasta and cook 1 minute less than al dente, about 8 minutes or according to package instructions. Reserve 2 cups of the cooking water. Drain the pasta and set it aside.

Step 5

When the garlic is ready, remove from the oven, unwrap, and set aside until the garlic is cool enough to handle, about 5 minutes. Squeeze the roasted garlic cloves out of their skins into a small bowl.

Step 6

Pour 3 tablespoons of the olive oil in a large skillet, then arrange the sliced garlic in a single layer in the oil. Turn the heat to medium. Cook, stirring frequently, until the garlic is golden-brown and crisp, about 5 minutes. Use a slotted spoon to transfer the garlic chips to a paper towel-lined plate to drain and sprinkle with kosher salt.

Step 7

Add the roasted garlic cloves and 1/4 teaspoon red pepper flakes to the oil in the skillet. Cook, breaking the cloves up with a wooden spoon, until fragrant, 2 to 3 minutes.

Step 8

Add the reserved pasta water and bring to a vigorous simmer over medium-high heat. Simmer until the liquid is reduced by half, about 5 minutes. Add the bucatini and toss continuously until the sauce thickens and coats the pasta, 1 to 2 minutes.

Step 9

Remove from the heat. Add the remaining 1 tablespoon olive oil and parsley and toss to combine. Taste and season with kosher salt as needed. Serve immediately, topping each serving with lots of grated Parmesan cheese and a sprinkle of garlic chips.