1 In a large nonstick skillet, melt butter. Add olive oil, onions and salt. Cover and cook over low heat about 20 minutes and then uncover and turn heat to medium.2 Stir frequently and cook until onions are brown and caramelized – about 5 minutes.3 In the meantime, cook pasta according to package directions. Drain and keep warm.4 Stir together onions, pepper, dill, parsley and salmon. Combine with pasta; sprinkle Parmesan cheese over top and serve immediately.