Bring a large pot of salted water to a rolling boil over high heat. Add spaghetti or linguine, cooking until al dente, approximately 8-10 minutes. Reserve ½ cup of pasta cooking water before draining.

In a large skillet, heat olive oil over medium heat for 1-2 minutes. Add minced garlic, stirring until fragrant, about 1-2 minutes.

Add sardines to the skillet, cooking for 2-3 minutes, stirring gently to incorporate.

Zest and juice the lemon into the skillet, stirring in red pepper flakes if desired.

Combine cooked pasta with the sardine mixture, adding reserved pasta water gradually until desired consistency is reached.

Adjust seasoning with salt and black pepper as needed. Garnish with parsley and Parmesan before serving.