Preheat the oven to 400°F (200°C). Slice the tops from the garlic heads to expose the cloves. Drizzle lightly with olive oil, wrap in foil, and roast for about 40–50 minutes, until the cloves are very soft. Cool slightly, squeeze out the roasted garlic, and mash. Set aside.

Set the oven to broil. Arrange the red bell pepper quarters skin-side up on a foil-lined baking sheet.

Broil the peppers for 10–15 minutes, or until their skins are well blackened and blistered. Transfer them to a covered heatproof bowl or sealed food-safe bag and let them steam for about 10 minutes.

Peel away the loosened pepper skins and roughly chop the softened peppers. Set aside.

Bring a large pot of generously salted water to a boil. Cook the fettuccine according to the package directions until al dente. Drain and set aside.

Meanwhile, heat the olive oil in a large pot over medium heat. Add the diced onion and cook for about 5 minutes, until tender and translucent.

Transfer the roasted peppers, roasted garlic, and cooked onion to a blender or food processor. Blend until completely smooth.

Melt the butter in the same pot over medium heat. Carefully pour in the red pepper puree.

Add the vegetable or halal chicken broth, heavy cream, and milk. Season with salt and black pepper. Stir well and gently heat the sauce until smooth and warmed through.

Remove the pot from the heat. Stir in the freshly grated Parmesan and chopped parsley until the cheese melts into the sauce.

Add the cooked pasta in batches, gently tossing until every strand is coated. Your Roasted Garlic and Red Pepper Fettuccine Alfredo should have a smooth, velvety sauce that clings easily to the pasta.

Serve immediately with additional Parmesan, parsley, and freshly ground black pepper if desired.