Like a vegetarian spaghetti carbonara! Meaty pistachios stand in for guanciale, cream amps up the usual eggs and cheese, homemade breadcrumbs add crunch, and a heap of lemon zest brightens up the whole dish.
Grate 2 1/2 teaspoons zest from lemons, then remove remaining zest in long strips with a vegetable peeler. Slice zest thinly (or remove zest with a channel zester); set aside. Squeeze 2 teaspoons of juice from 1 lemon (reserve rest of this lemon for another use).
In a food processor, pulse bread into very coarse breadcrumbs (you should have 1 cup). Melt 2 tablespoons butter in a small skillet over medium-high heat. Add breadcrumbs and 1 teaspoon grated zest. Cook, stirring, until crumbs are golden and crisp, about 3 minutes. Remove from pan; let cool completely. In a large bowl, whisk together eggs, yolks, cream, cheese, and remaining 1 1/2 teaspoons grated zest.
Bring a large pot of salted water to a boil. Add pasta and cook until al dente, about 2 minutes less than package directions. Drain, reserving 1 cup pasta water; add pasta to bowl with cheese mixture. Season with a generous amount of pepper and some salt. Use tongs to toss until pasta is fully coated. Add remaining 4 tablespoons butter and lemon juice; toss until a creamy sauce forms. (If necessary, thin with a little pasta water, 1 tablespoon at a time.)
Serve pasta sprinkled with breadcrumbs, pistachios, more cheese, chives, and julienned lemon zest.