Bring a large pot of generously salted water (about 1 tablespoon salt per 4 quarts water) to a rolling boil. Add pasta and cook until 1 minute less than al dente (about 8-9 minutes for most dry pasta). Reserve 1 cup of pasta water before draining. Drain pasta (do not rinse).

While pasta cooks, pat shrimp dry with paper towels. Season with a pinch of salt and pepper.

In a large 12-inch skillet, heat 2 tablespoons butter and 2 tablespoons olive oil over medium-high heat until butter melts and sizzles. Add shrimp in a single layer (work in batches if needed). Cook undisturbed for 1-2 minutes until bottoms are pink and lightly browned. Flip and cook 1 minute more until opaque throughout. Transfer shrimp to a plate (they will finish cooking later).

Reduce heat to medium. Add remaining 2 tablespoons butter and 1 tablespoon olive oil to the skillet. Add sliced garlic and red pepper flakes. Cook, stirring constantly, for 30-45 seconds until fragrant and garlic is just golden — do not let it burn.

Pour in white wine and lemon juice. Increase heat to medium-high and bring to a simmer. Scrape up any browned bits from the bottom of the pan (this is flavor). Simmer for 2-3 minutes until the liquid reduces by about half.

Add the drained pasta, cooked shrimp (and any accumulated juices), and 1/4 cup of the reserved pasta water. Toss gently with tongs for 1-2 minutes until the sauce coats the pasta and thickens slightly. If the pasta seems dry, add more pasta water 1 tablespoon at a time.

Remove from heat. Toss in chopped parsley. Taste and adjust salt and pepper. Serve immediately, garnished with lemon zest if desired.