Wash the red bell peppers, slice them in half lengthwise, and remove the seeds and stems. Arrange the pepper halves cut-side down on a baking sheet lined with parchment paper and drizzle with olive oil.
Roast the peppers in the preheated oven for 20-25 minutes until the skins blister and turn blackened. Remove from the oven and let cool for a few minutes.
Peel off the blistered skins from the cooled peppers and transfer the roasted flesh into a blender. Add the minced garlic and blend until smooth; set aside.
In a large saucepan over medium heat, pour in the heavy cream and let it simmer gently. Gradually whisk in the blended roasted red pepper mixture until smooth.
Increase the heat slightly and stir in the freshly grated Parmesan cheese and Italian seasoning. Stir until the cheese is fully melted and the sauce is creamy. Adjust seasoning with salt and freshly cracked black pepper as needed.
Bring a large pot of salted water to a boil and cook the fettuccine according to package instructions, about 8-10 minutes, until al dente. Drain the pasta and set aside, reserving a small cup of pasta cooking water.
Add the drained fettuccine to the saucepan with the creamy roasted red pepper sauce. Toss gently to coat, adding reserved pasta water if necessary to reach desired consistency.
Plate the pasta immediately, garnishing with fresh basil leaves.
Notes
For a spicier kick, add red pepper flakes to the sauce.