Bring a large pot of salted water to a boil. Wash and dry all produce. Trim and thinly slice scallions, separating whites from greens. Zest and quarter lemon. Trim ends from zucchini. Using a peeler, shave zucchini lengthwise into ribbons, rotating until you get to the seedy core; discard core.

Rinse and pat shrimp dry with paper towels. Season with salt and pepper. Heat a large drizzle of olive oil in a large, preferably nonstick, pan over medium-high heat. Add shrimp and cook, stirring, until pink and firm, 3-4 minutes. Turn off heat; remove from pan and set aside. Wipe out pan.

Heat 1 TBSP butter (2 TBSP for 4 servings) and a large drizzle of olive oil in same pan over medium heat. Add scallion whites and cook, stirring, until softened, 1-2 minutes. Add cream cheese and sour cream; reduce heat to low. Stir until smooth, 1 minute. Turn off heat.

Once water is boiling, add ravioli to pot and reduce heat to low. Cook until ravioli are tender and float to the top, 2-5 minutes. Scoop out and reserve 1 cup cooking water, then gently drain.

Add zucchini ribbons, shrimp, ⅓ cup cooking water, 1 TBSP butter (2 TBSP for 4 servings), and juice from 2 lemon wedges (4 wedges for 4) to pan with sauce. Stir over low heat until zucchini is tender, 2-3 minutes. Add ravioli and another 1 TBSP butter (2 TBSP for 4). Stir until thoroughly combined and butter has melted, 1-2 minutes. (TIP: If pan seems dry, add more cooking water, a splash at a time, until a creamy sauce forms.) Season with salt and pepper.

Divide ravioli between plates. Sprinkle with Parmesan, scallion greens, and as much lemon zest and chili flakes as you like. Serve with remaining lemon wedges on the side.