green angel hair with garlic butter
½ cup (4 ounces, or 115 grams) salted or unsalted butter, sliced into a few pieces
1 large head garlic, halved crosswise
1 pound (455 grams) thin spaghetti, such as angel hair or capellini
5 ounces (140 grams) baby spinach
Freshly ground black pepper and/or red-pepper flakes
Pecorino Romano, to finish
Heat oven to 375
Arrange the butter slices across the bottom of a small (2-cup) baking dish.
Sprinkle with salt: ¼ teaspoon if using salted butter, and ½/ teaspoon if unsalted. Place the garlic halves, cut side down, over the butter and salt.
Cover the dish tightly with foil, and bake for 35 to 45 minutes, until the garlic is absolutely soft when poked with a knife and golden brown along the cut side. Carefully remove the foil. Empty the garlic cloves into the melted butter. I do this by lifting the peels out of the butter with tongs, allowing most cloves to fall out, and using the tip of a knife to free the cloves that don't. Scrape any browned bits from the sides of the baking vessel into the butter.
green angel hair with garlic butter (continued)
Meanwhile, cook your pasta in well-salted water until 1 to 2 minutes shy of done. Before you drain it, ladle 1 cup pasta water into a cup, and set it aside. Hang on to the pot you cooked the pasta in.
Place the spinach in a blender or food-processor bowl, and pour the garlic butter over it, scraping out any butter left behind. Add another ¾ teaspoon salt and several grinds of black pepper, and/or a couple pinches of red-pepper flakes, and blend the mixture until totally smooth. If it's not blend-ing, add 1 to 2 tablespoons of reserved pasta water to help it along. Taste for seasoning, and add more if needed.
Pour the spinach sauce into the empty spaghetti pot, and add the drained pasta and a splash of pasta water. Cook over medium-high heat, tossing constantly, for 2 minutes, until the sauce thickens and coats the spa-ghetti. If the pasta sticks to the bottom of the pot, add more reserved pasta water in splashes to get it moving. Tip the pasta into a serving bowl, finish with more salt and pepper and freshly grated cheese, and hurry-it disappears fast.