Bring a large pot of salted water to boil and add noodles, cooking them to just the tiniest bit below done, about 30 seconds to 1 minute early. Before you drain them, reserve 1 cup of the cooking water. Drain the noodles. Melt 5 tablespoons of the butter in the empty pot. [Here is where you’d brown it, or cook in garlic, should you wish.] Add the drained pasta and most of the reserved cooking water. Cook them together over medium-high heat, stirring constantly, until all but a thin puddle of butter-water has absorbed and the noodles are nicely coated, splashing in more cooking water as needed to keep things moving. Season with salt, as needed. Transfer the noodles to a serving bowl, scraping all of the buttery gloss at the bottom of the pot over the noodles, and finish the bowl the last tablespoon of butter, letting it melt over the noodles. Add a few flakes of sea salt [or any of the other ingredients listed above, if you wish] and dive right in.