Get a big pot boiling with salted water. Cook pasta till al dente, and reserve ½ cup pasta water before draining.
Heat skillet over medium, melt butter, and add onions with salt. Stir often until deeply golden and caramelized, about 20–25 minutes.
Add oregano and smoked paprika, stirring for about a minute to bloom the spices.
Stir in chili crunch and heavy cream. Bring to gentle simmer and let cream thicken slightly.
Add drained pasta to skillet and toss well. Use pasta water if sauce needs thinning.
Stir in Parmesan until melted and sauce becomes creamy. Serve hot with garnish.
Notes
Top with chopped parsley and extra chili crunch for added heat. Store leftovers up to 3 days or freeze for 1 month. Reheat gently with splash of cream or water.