Bring a large pot of salted water to a rolling boil over high heat. Once boiling, add the spaghetti and cook for 8–10 minutes until al dente, stirring occasionally. Reserve about ½ cup of the starchy pasta water before draining the spaghetti. Toss drained pasta with olive oil to prevent sticking.

In a large skillet, melt 2 tablespoons of unsalted butter with 1 tablespoon of olive oil over medium-low heat. Once melted, add minced garlic and sauté for 1–2 minutes, stirring continuously until fragrant and just starting to turn golden. Be careful not to brown the garlic.

Sprinkle in 1 teaspoon of Italian seasoning and the zest of 2 lemons. Stir for about 30 seconds, allowing the herbs and zest to toast slightly. This builds flavor.

Pour in the juice of 1 lemon and simmer for 1–2 minutes, allowing the flavors to meld. The sauce should thicken slightly and be glossy.

Add the cooked spaghetti into the skillet, turning the heat to low. Gradually pour in the reserved pasta water, stirring to emulsify. Mix until the pasta is coated and the sauce is creamy.

Remove from heat and fold in the chopped fresh parsley, adjusting seasoning with kosher salt and black pepper to taste.

Plate the pasta hot, garnishing with grated Parmesan cheese and crushed red pepper flakes if desired. Serve immediately.