Boil a large pot of generously salted water over high heat. Once rolling, add your pasta and cook according to package directions until al dente. While pasta boils, start your sauce.
Heat olive oil in a large skillet over medium heat. Add minced shallot and cook for 3 minutes until soft and translucent.
Stir in sliced garlic and red pepper flakes. Sauté for exactly 45 seconds until fragrant—be careful not to burn the garlic.
Gently mash the drained sardines into the skillet. Add lemon zest and vegetable broth. Stir continuously for 2 minutes to create a warm, emulsified base.
Drain pasta, reserving 1/2 cup of starchy pasta water. Immediately toss the noodles into the skillet with the sauce.
Pour in fresh lemon juice and toss vigorously for 1–2 minutes. Add reserved pasta water a splash at a time until the sauce is slightly thick and glossy, clinging beautifully to every strand.
Remove from heat. Fold in chopped parsley and season with salt and freshly cracked black pepper. Serve immediately!