Boil the pasta: Bring a large pot of salted water to a boil. Add pasta and cook until just shy of al dente. Reserve 1 cup of pasta water before draining.

Blanch the asparagus: During the last 2–3 minutes of pasta cooking, add asparagus to the pot. Cook until bright green and crisp-tender. Drain with the pasta and set aside.

Sauté aromatics: In a large skillet over medium heat, warm olive oil and butter. Add garlic and a pinch of red pepper flakes. Cook 30–60 seconds until fragrant, not browned.

Build the sauce base: Stir in lemon zest and broth. Let it simmer for 1 minute to meld flavors.

Add cream: Pour in the heavy cream and reduce heat to medium-low. Simmer 2–3 minutes, stirring, until slightly thickened.

Cheese and lemon: Whisk in Parmesan until smooth. Add 2 tablespoons lemon juice, then taste. Add more lemon juice if you want extra brightness.

Toss the pasta: Add the drained pasta and asparagus to the skillet. Toss gently, adding reserved pasta water as needed, a splash at a time, to create a silky coating.

Season: Add salt and freshly ground black pepper to taste. Stir in chopped parsley or chives.

Serve: Plate with extra Parmesan and lemon wedges. Serve immediately while glossy and hot.