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 (for 4 servings, zest 1 lemon and quarter both). Trim ends from zucchini. Using a peeler, shave zucchini lengthwise into ribbons, rotating as you go, 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 mediumhigh heat. Add shrimp and cook, stirring, until opaque and cooked through, 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 low heat. Add scallion whites and cook, stirring, until softened, 1-2 minutes. Turn off heat; stir in cream cheese and sour cream until smooth.

Once water is boiling, add ravioli to pot and reduce heat to low. Cook until ravioli are tender and floating to the top, 3-4 minutes. Reserve 1 cup pasta cooking water, then gently drain or use a slotted spoon to remove ravioli from pot.

Heat pan with sauce over low heat. Stir in 1/3 cup reserved pasta cooking water (1/2 cup for 4 servings) and juice from half the lemon. Add 2 TBSP butter; stir constantly until melted. Repeat with another 2 TBSP butter; cook until sauce is creamy, 2-3 minutes. (TIP: If sauce seems too thick, stir in more pasta cooking water a splash at a time.) Stir in shrimp and zucchini ribbons; cook until zucchini is tender, 1-2 minutes. Stir in ravioli to coat. Turn off heat. Taste and season with salt and pepper.

Divide ravioli mixture 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.