Put your knife away—store-bought pesto and precut broccoli florets mean no chopping required. Your Dutch oven pulls triple duty in this recipe by cooking the pasta, blanching the broccoli, and bringing the whole dish together, all in one pot.
Bring 10 cups water to a boil in a Dutch oven over high. Add fettuccine, and cook 6 minutes. Add broccoli florets to pasta; cook until pasta is al dente and broccoli is bright green and crisp-tender, about 3 minutes. Reserve 1/2 cup cooking liquid, and set aside. Drain pasta mixture.
Return pasta and broccoli to Dutch oven; reduce heat to low. Stir in pesto, mustard, lemon zest and juice, and salt. Add shrimp, and cook, stirring constantly, just until heated through, about 2 minutes, adding cooking liquid, 1 tablespoon at a time, if needed for creaminess. Top with Parmesan; serve immediately.