01 -
Bring large pot of cold water to rolling boil over high heat. Salt generously and add spaghetti. Cook stirring occasionally until al dente, about 8 minutes.
02 -
While pasta cooks, combine minced garlic, olive oil, salt, and red pepper flakes in large skillet. Warm over low heat, stirring occasionally, until garlic softens and turns golden, about 8 minutes.
03 -
Drain pasta in colander, reserving 1/4 cup cooking water. Add pasta and reserved water to garlic mixture. Mix well, then add parsley and lemon zest if using. Adjust seasoning to taste.
04 -
Transfer to large serving bowl or divide among individual dishes. Top with grated Parmigiano-Reggiano if desired and serve immediately.