Boil the spaghetti until al dente.
Cut the broccoli into large chunks.
Blanch the broccoli in a shallow layer of boiling water, drain well, pat dry, and chop into small pieces.
Sauté garlic and red pepper flakes in olive oil until fragrant.
Add the chopped broccoli and cook briefly.
Stir in lemon zest, lemon juice, grated pecorino Romano cheese, and kosher salt.
Toss with the drained spaghetti until combined.
