- 1/2 pound spaghettini (thin spaghetti)
 - 1/2 cup chopped red onion
 - 1/4 cup extra-virgin olive oil
 - 1 to 2 teaspoons sambal oelek or Sriracha sauce
 - 1/2 pound shelled cooked crabmeat, cut into 1-inch pieces (from about 1 1/4 pound thawed frozen king crab legs)
 - 2 pieces preserved lemon , pulp discarded and rind rinsed and finely chopped (1 tablespoon)
 - 1/3 cup finely chopped flat-leaf parsley
 - 2 tablespoons salted butter
 
- Cook spaghettini in a pasta pot of boiling salted water (3 tablespoons salt for 6 quarts water) until al dente.
 - Meanwhile, cook onion in oil in a large heavy skillet over medium heat, stirring, until softened. Stir in sambal oelek and cook 1 minute, then add crabmeat. Reduce heat to low and cook, stirring frequently, just until crabmeat is heated through.
 - Drain pasta, then add to skillet along with remaining ingredients and toss to coat well.