In a large pot, bring salted water to a rolling boil. Add spaghetti and cook according to package instructions until al dente. Drain and reserve 1 cup of pasta water.

Heat a generous splash of olive oil in a large skillet over medium heat. Toss in chopped red onion and sauté until soft and translucent, about 4–5 minutes.

Add minced garlic to the skillet. Stir frequently until fragrant, about 1–2 minutes.

Gently place large shrimp into the skillet. Sauté until pink and opaque, about 3–4 minutes.

Sprinkle in dried oregano and red pepper flakes. Stir well to distribute the flavors evenly.

Pour in dry white wine and allow to simmer for 3–4 minutes until reduced slightly.

Stir in the zest and juice of lemon, followed by chopped tomatoes and parsley. Mix until well-coated, about 2 minutes.

Toss the cooked spaghetti into the shrimp mixture, adding reserved pasta water bit by bit to reach desired consistency.

Season with freshly ground black pepper and plate up. Generously garnish with freshly grated parmesan cheese.