In a large pot, bring 4 quarts of water to a rolling boil over high heat. Add 2 tablespoons of salt.

Add the spaghetti to the boiling water. Stir immediately to prevent sticking. Cook according to package directions (8-10 minutes), or until al dente. Reserve 1 cup of pasta water.

Drain the spaghetti in a colander.

While the spaghetti is cooking, heat the olive oil in a large skillet over medium heat. Add the minced garlic and red pepper flakes (if using). Sauté for 1-2 minutes, or until fragrant and lightly golden.

Add the drained spaghetti to the skillet with the garlic oil. Toss to coat. Pour in about 1/2 cup of the reserved pasta water. Toss again. Add more pasta water, a tablespoon at a time, until desired consistency is reached.

Stir in the chopped fresh parsley and grated Parmesan cheese. Season with salt and pepper to taste. Toss until cheese is melted and sauce is creamy.

In a medium bowl, combine the softened butter, minced garlic, chopped fresh parsley, grated Parmesan cheese, and garlic powder (if using). Season with salt and pepper to taste. Mix well.

Slice the Italian bread lengthwise, creating two long halves.

Generously spread the garlic butter mixture over the cut sides of both bread halves.

Preheat oven to 375°F (190°C).

Place the garlic bread halves on a baking sheet, cut-side up. Bake for 10-12 minutes, or until golden brown and the garlic butter is melted and bubbly.

Broil for the last 1-2 minutes for extra crispy garlic bread. Watch carefully.

Remove the garlic bread from the oven and let it cool slightly before slicing into individual pieces.

Divide the spaghetti among individual plates.

Sprinkle with extra grated Parmesan cheese and a pinch of fresh parsley, if desired.

Serve the spaghetti immediately with the warm, garlicky bread on the side.