SERVES 4 TO 6 * 1/3 cup whole shelled natural pistachio nuts * 2 cups water * 2 teaspoons fine sea salt * 1 pound thin asparagus, washed, woody ends removed, and stalks cut into thirds * ¼ cup (½ stick) unsalted butter * 1 large clove garlic, peeled and cut in half lengthwise * ¼ teaspoon ground white pepper * 1/3 cup dry white wine * 1 cup Half & Half ¼ cup heavy cream * 1 pound penne * ½ cup freshly grated Parmigiano-Reggiano cheesePreheat oven to 350ºF.
Spread the nuts on an aluminum pie plate and toast them in the oven for 5 to 7 minutes, watching carefully so they do not burn. Transfer the nuts to a cutting board, mince them, and set aside.
Bring the water to boil in a pot. Add ½ half teaspoon of the salt and the asparagus. Cook, uncovered, over medium-high heat just until a knife tip is easily inserted into the asparagus, about 3 minutes. Drain and set aside.
In a sauté pan, melt the butter over medium heat. Add the garlic and press on it with a wooden spoon to release its flavor. When the garlic starts to brown around the edges, remove and discard it. Add the asparagus and white pepper, raise the heat to high, and pour in the wine. Stir the mixture carefully for about 1 minute. Reduce the heat to medium. Mix the half and half and heavy cream together and pour it over the asparagus mixture. Cook for 2 minutes; the sauce should be thick and velvety like heavy cream. Stir in the remaining 1½ teaspoons salt. Keep the mixture warm while the penne cooks.
Cook the penne according to the package directions. Drain and return to the cooking pot. Pour the asparagus sauce over the penne and stir carefully over low heat. Add the cheese and continue to stir until the cheese melts. Transfer the penne to a serving platter, sprinkle the nuts over the top, and serve immediately.