Start by bringing a large pot of water to a boil. Add 1 tablespoon of salt and 1 teaspoon of oregano to season the water—it infuses subtle herbal notes into the pasta itself.

Meanwhile, finely chop the onion, garlic, and fresh parsley. Juice half a lemon and set it aside.

In a medium pan over medium-low heat, heat 3 tablespoons of olive oil. Add the chopped onions and sauté until golden and soft, stirring often to prevent burning. This step brings out their natural sweetness and adds depth to the sauce.

Once the onions are golden, stir in the minced garlic. Sauté for 30 seconds until fragrant.

Add red chili flakes and paprika to the pan. Cook for another 30 seconds, stirring continuously to bloom the spices in the oil. Turn off the heat. Reserve about 2 teaspoons of this chili onion crisp to use later as a garnish.

Once the water reaches a rolling boil, add the spaghetti and cook for 1–2 minutes less than the package instructions indicate. You want it just shy of al dente since it will finish cooking in the sauce.

Before draining, reserve about ½ cup of pasta water.

Add the drained spaghetti directly into the pan with the spicy sauce. Pour in the reserved ½ cup of pasta water and lemon juice. Turn the heat to medium and stir everything together.

Cook for about 1–2 minutes until the sauce thickens slightly, becomes glossy, and coats the pasta beautifully. Taste and adjust seasoning—typically, the salt from the pasta water is enough, but you can add more if needed.

Divide the pasta between plates and top with the reserved chili onion crisp, freshly chopped parsley, a little more lemon juice, and a generous sprinkle of grated Parmesan.