Step 1: Roast the Garlic
Preheat your oven to 400°F (200°C). Cut the top ¼ inch off the garlic heads to expose the clove tops. Place each head on a piece of aluminum foil, drizzle with olive oil, sprinkle with salt, and wrap tightly. Place on a baking sheet and roast for 35-40 minutes until the cloves are golden and soft. Let cool, then squeeze the roasted cloves out of their skins and mash into a paste. (This can be done up to 3 days ahead!)

Step 2: Cook the Pasta
Bring a large pot of salted water to a rolling boil (the water should taste like the sea!). Add the fettuccine and cook according to package directions until al dente, usually 8-10 minutes. Reserve 1 cup of pasta cooking water before draining. Drain the pasta and set aside.

Step 3: Start the Alfredo Sauce
In a large skillet over medium heat, melt the butter. Add the mashed roasted garlic and sauté for 1-2 minutes until fragrant, stirring constantly to prevent burning. This step releases even more of that sweet garlic flavor into the butter.

Step 4: Add the Cream
Pour in the heavy cream and bring to a gentle simmer. Reduce heat to medium-low and let it simmer for 3-4 minutes, stirring occasionally, until it thickens slightly. Do not let it boil rapidly or the cream may break.

Step 5: Incorporate the Cheese
Remove the skillet from heat. Gradually whisk in the freshly grated Parmesan cheese, adding it in three batches and stirring well between each addition until the sauce is smooth and creamy. The residual heat will melt the cheese perfectly without making it stringy.

Step 6: Season the Sauce
Add salt, pepper, and nutmeg (if using). Taste and adjust seasoning as needed. Remember that Parmesan is salty, so start with less salt and add more if needed.

Step 7: Combine Pasta and Sauce
Return the skillet to low heat. Add the drained pasta to the sauce and toss gently using tongs, coating every strand thoroughly. If the sauce seems too thick, add reserved pasta water, 2 tablespoons at a time, until you reach your desired consistency. The starchy pasta water helps the sauce cling to the noodles beautifully.

Step 8: Serve Immediately
Transfer the pasta to serving plates or a large platter. Garnish with fresh chopped parsley and extra grated Parmesan. Serve immediately while hot and creamy!