Bring a large pot of salted water to a boil. Cook ½ box of spaghetti according to package instructions until al dente. Reserve ½ cup of pasta water (just in case), then drain and set aside.
In a large skillet or sauté pan, melt 2 tablespoons of butter over medium-low heat. Add your thinly sliced onion and cook slowly, stirring occasionally, until the onions are soft, golden, and jammy—this should take about 12–15 minutes. Don’t rush it; this step builds major flavor.
Once your onions are caramelized, stir in ½ teaspoon salt, 2 teaspoons oregano, 2 teaspoons smoked paprika, and a generous heaping tablespoon of chili crunch. Let everything toast together for 1–2 minutes until fragrant.
Slowly add 1 pint of heavy cream to the pan, stirring to combine. Bring the mixture to a gentle simmer and let it bubble for 3–4 minutes until slightly thickened.
Lower the heat and mix in ¼ cup of freshly grated Parmesan cheese. Stir until melted and creamy. If the sauce feels too thick, add a splash of reserved pasta water to loosen it up.
Add your cooked spaghetti straight into the sauce and toss until every strand is coated in that rich, spicy cream.
Plate it up and finish with freshly chopped parsley and a little more chili crunch on top for extra heat and texture.
