Place a large pan over medium heat and melt butter.
Add breadcrumbs and toast for 1 minute.
Stir in salt and chives. Remove from heat, transfer to a bowl and set aside.
Place a large pot over high heat and bring to a boil. Once water is boiling, add a small handful of salt and spaghetti.
Cook spaghetti for 6 to 7 minutes, stirring occasionally, until pasta is al dente. Strain pasta into a colander, reserving ½ cup pasta water.
Using a paper towel, wipe out the same pan used for breadcrumbs. Place pan over medium heat and add oil.
Add shallots and garlic and sauté for 30 seconds, just until the mixture becomes fragrant, but hasn’t started to brown.
Add lemon zest, juice and crushed pepper flakes and continue to cook for another 30seconds.
Add pasta and pasta water and toss together. Cook until half the liquid has evaporated, about 1 minute. Add parmesan then season with salt and pepper and toss together until pasta is evenly coated.
Transfer pasta to serving bowls or plates and top with breadcrumb mixture, more lemon zest and more grated parmesan. Serve.
