Begin by bringing a large pot of salted water to a boil over high heat. Add the spaghetti and cook it according to the package instructions, typically 8-10 minutes, until it's al dente. Once cooked, drain the pasta well in a colander and set it aside.

In a large skillet, melt 1 tablespoon of unsalted butter over medium heat until bubbly. Carefully add the shrimp in a single layer, cooking for about 1-2 minutes per side until they turn pink and opaque. Once cooked, remove the shrimp and set aside.

Using the same skillet, add an additional 2 tablespoons of unsalted butter and let it melt. Add the minced garlic and red pepper flakes (if using), sautéing for about 30 seconds until fragrant.

Pour in ½ cup of dry white wine, scraping any browned bits from the skillet. Add in the lemon zest and juice, allowing the mixture to boil gently for about 1 minute.

Lower the heat and whisk in the remaining 2 tablespoons of butter until the sauce is creamy. Return the cooked shrimp to the skillet.

Toss the drained spaghetti into the skillet with the shrimp and sauce, ensuring each strand is coated.

Transfer to serving plates, garnish with chopped parsley, and serve immediately with lemon wedges.