Spaghetti with Mascarpone, Meyer Lemon, Spinach, and Hazelnuts

serves two as a main course

1 teaspoon Meyer lemon zest (from about 1/2 lemon)
juice from one Meyer lemon (about 1/4 cup)
1/2 cup mascarpone cheese
1/2 teaspoon salt
a few grinds of fresh pepper
1/4 teaspoon freshly grated nutmeg
1/2 pound spaghetti
5 cups (loosely packed) fresh spinach, washed, spun dry, and roughly chopped
1/2 cup chopped, toasted hazelnuts

Combine the zest, lemon juice, mascarpone, salt, pepper, and nutmeg in a bowl. Whisk to combine.

Bring a pot of water to boil and salt generously. Cook the pasta until al dente, taking it off the heat about 1 to 2 minutes before you would normally remove it. Drain, reserving about 1/2 cup of the pasta water.

Return the pasta to the pot, and set over low heat. Stir in the mascarpone sauce. Add the spinach and toss so that the spinach begins to wilt. Add about 1/4 cup of the pasta water (more if necessary) to keep the sauce fluid but not too watery. Continue to cook and toss until the spinach is cooked. Add the hazelnuts and stir to combine. Serve immediately.