1-½ cups(175g) butternut squash cut into ¼-inch (1cm) cubes
¼ cup (55g) toasted pine nuts
½ teaspoon (3g) smoked salt
Whisk together egg yolks, cheese, parsley, pepper and kosher salt in a large heatproof bowl; set aside.
Bring a large pot of well salted water to a boil; add spaghetti and cook according to package direction to al dente. Reserve ½ cup (120ml) cooking water, drain pasta and set aside.
Heat oil in a large non-stick skillet over medium heat. Add squash and cook, stirring occasionally until softened and beginning to brown, about 5 to 7 min. Remove pan from heat, add pasta and stir to coat and heat pasta; set aside.
Whisking constantly to avoid curdling, slowly stream in 3 tablespoons (45ml) pasta water into yolk mixture. Pour egg mixture onto the spaghetti and mix for about 5 seconds. Transfer everything back into the egg yolk bowl, stirring continually. If the sauce seems a bit thick, add a little more pasta water, 1 tablespoon (15ml) at a time until sauce is loose and velvety.
Toss with pine nuts and smoked salt and serve topped with more pecorino, parsley and pepper, if desired.