Bring a large pot of water to a rolling boil and salt it generously (about 1 tbsp kosher salt per 4–5 liters). Salted pasta water seasons the pasta from the inside and becomes a flavor-rich binder for the sauce. Add the linguine and cook until just shy of al dente (check package directions and subtract 1–2 minutes) because it will finish cooking in the sauce.

While the pasta heats, prepare an ice bath (bowl of ice + cold water). This is for shocking the asparagus after a quick blanch — it stops carryover cooking and preserves vivid color and snap.

When the pasta water returns to a boil and you have 3 minutes left on the pasta timer (or about 2–3 minutes before your desired doneness), add the asparagus pieces to the boiling water for 1–2 minutes until bright green and just tender. This timing softens the fibrous base while keeping tips crisp. Remove the asparagus immediately and plunge into the ice bath to halt cooking. Reserve 1 cup of the pasta cooking water and drain the pasta.

Pat the shrimp dry thoroughly with paper towels and season lightly with kosher salt and a few grinds of black pepper. Dry shrimp sear and color better; surface moisture prevents a good crust and can steam them instead.

In a large, wide sauté pan (big enough to hold the pasta), warm 2 tablespoons of olive oil over medium-high heat until shimmering but not smoking. Add the seasoned shrimp in a single layer and sear 1.5–2 minutes per side (depending on size) until pink and just cooked through. Sear to develop a thin golden edge that adds flavor via Maillard reaction. Transfer shrimp to a plate and tent loosely with foil to keep warm; avoid overcooking — they'll finish briefly in the sauce if needed.

Lower the heat to medium, add the remaining 2 tablespoons olive oil to the pan, then add the minced garlic and red pepper flakes. Cook, stirring constantly, 30–45 seconds until fragrant but not browned — browning garlic turns it bitter. This step infuses the oil with garlic and chili heat, forming the base of the sauce.

Add the halved cherry tomatoes and a pinch of salt. Cook 2–3 minutes, stirring occasionally, until the tomatoes begin to blister and release juices. The blistering concentrates the tomatoes’ sweetness and creates a loose pan sauce that will cling to the pasta.

Return the seared shrimp and the blanched asparagus to the pan. Add the lemon zest and lemon juice. Toss gently to combine and warm through 1–2 minutes. The hot pan will lift the shrimp's flavor and marry the lemon with the garlic-tomato base; adding lemon at this stage brightens the dish without cooking away the fresh citrus aroma.

Add the drained linguine to the pan along with 1/2 cup of the reserved pasta water. Toss vigorously (tongs are ideal) for 1–2 minutes to allow the starchy water to emulsify with the oil into a glossy sauce that coats the pasta. If the sauce feels dry, add additional pasta water, 1–2 tbsp at a time, until you reach a silky consistency.

Remove the pan from heat and stir in the butter (if using) and most of the chopped parsley. The butter enriches and rounds the flavors and helps the sauce cling to the noodles; adding it off the heat prevents separation. Taste and adjust seasoning with salt, pepper and more lemon juice if needed.

Plate the linguine, arranging shrimp and asparagus on top. Finish with the remaining parsley, a light drizzle of extra virgin olive oil (optional), a few grinds of black pepper and more lemon zest for fragrance. Serve immediately so the textures stay fresh — warm pasta, tender-crisp asparagus and juicy tomatoes.

Leftovers: store cooled leftovers in an airtight container in the refrigerator for up to 2 days. Reheat gently in a skillet with a splash of water or broth to avoid overcooking the shrimp.