1 pound whole wheat spaghetti
2 tablespoons butter
1 1/2 tablespoons minced fresh garlic
1/2 teaspoon red pepper flakes (or to taste)
4 medium zucchini (ends trimmed, coarsely grated)
1 cup ricotta cheese (preferably whole milk)
  grated zest of 2 lemons
1/4 cup minced fresh basil
1/2 cup grated parmesan or Piave Vecchio cheese
1/2 cup toasted bread crumbs (see note below)