Peel the garlic

• Place the garlic bulbs in a sealed container.
• Microwave for 15 seconds, then shake vigorously to loosen the skins.
• Peel the cloves.

Roast the garlic in oil

• Add the olive oil to a pan with the peeled garlic.
• Cook over medium heat until the garlic is golden.

Blend the garlic sauce

• Transfer the garlic and oil to a blender and add the butter.
• Blend until smooth.

Finish the sauce

• Add the tomato paste, Parmesan cheese and basil to the blended sauce.
• Mix well.

Cook the spaghetti

• Cook the spaghetti in salted boiling water until al dente.
• Drain, keeping a little cooking water.

Combine and serve

• Toss the pasta with the garlic sauce, loosening with cooking water if needed.
• Sprinkle with extra Parmesan and chili flakes.