Bring a large pot of salted water (about 4 quarts) to a boil over high heat.

Pat the shrimp dry with paper towels and season lightly with salt and black pepper; set aside.

Add the pasta to the boiling water and cook until al dente according to package directions, 9–12 minutes. Reserve 1 cup of pasta water, then drain.

Meanwhile, melt 2 tablespoons of the butter with the olive oil in a large skillet over medium heat.

Add the minced garlic and red pepper flakes; sauté for 1 minute until fragrant, stirring constantly.

Add the shrimp in a single layer and cook for 2 minutes without moving. Flip and cook for another 1–2 minutes until the shrimp are opaque and pink.

Stir in the broth and lemon juice, bring to a gentle simmer for 1 minute, then add the remaining 4 tablespoons butter, stirring until melted and the sauce is emulsified.

Add the drained pasta to the skillet and toss to coat, adding reserved pasta water a splash at a time until the sauce clings to the noodles.

Remove from heat; stir in lemon zest, parsley, and garlic powder. Taste and adjust with salt and black pepper as needed.

Serve immediately while hot, garnished with additional parsley if desired.