Spring Vegetable Fettuccine

Bring a large pot of generously salted water to a boil. Add the pasta and cook according to package directions until al dente, tender but slightly firm. Reserve 1/2 cup of the pasta water, then strain the pasta and toss with a splash of oil in the colander.

Meanwhile, slice the mushroom caps into 1/4-inch-thick strips. Snap the woody ends off the asparagus and cut into 2-inch lengths. Heat a large skillet over medium heat, and add 2 tablespoons of the butter. When the butter melts, raise the heat to medium-high and add the mushrooms in 1 layer. Cook, without moving, until the undersides have browned, 1 to 2 minutes, then stir and cook until golden about 2 minutes more. Add the asparagus, another tablespoon of butter, and 1/2 teaspoon salt and continue to cook, stirring occasionally until the asparagus is tender and the mushrooms are browned, 2 to 4 minutes. Transfer the vegetables to the colander with the pasta.