Bring to boil a big pot of generously salted water. Cook the spaghetti until al dente, about 9 minutes.
While the spaghetti cooks, shave the carrots with a vegetable peeler.
Strain the cooked pasta, reserving about a mug full of the pasta water.
In a medium bowl, toss together the hot pasta and carrot ribbons along with a glug of good olive oil.
Add the miso, lemon, and a splash of the pasta water and give it a stir.
Toss in the grated parmesan and torn basil leaves and give it another stir.
Salt to taste and serve topped with bread crumbs.