Cajun pasta — fettuccine or penne tossed with andouille, shrimp, the holy trinity, garlic, cayenne, and a cream sauce — represents the Cajun-Italian crossover that happened in American restaurants in the 1980s-90s when Prudhomme's Cajun revolution (LA4-04) collided with Italian-American pasta culture. The dish appears on the menu of every Cajun-themed restaurant in America and many Italian-American restaurants as well. It has no Louisiana ancestor (Louisiana uses rice, not pasta, as its starch) but it is a legitimate fusion product — the Cajun seasoning, the trinity, and the andouille applied to an Italian-American pasta format.
Fettuccine, penne, or rigatoni tossed with: sliced andouille (seared until browned), shrimp (sautéed until just pink), the holy trinity (diced fine, sautéed), garlic, cayenne, black pepper, and a cream sauce (heavy cream reduced with Parmesan, or a roux-based cream sauce). The sauce should coat the pasta; the andouille should provide smoke; the shrimp should be tender; the cayenne should build over several bites.
1) Sear the andouille first — the rendered fat becomes the sauté medium for the trinity and the fond flavours the cream sauce. 2) Don't overcook the shrimp — add them last, 2-3 minutes before tossing with pasta. 3) The cream sauce should be tight enough to coat, not pool. 4) Cayenne must be present — this is Cajun pasta, not alfredo with sausage.
Crawfish Monica (LA4-12) is the Louisiana-specific version using crawfish instead of shrimp; Cajun pasta is the national-restaurant adaptation using more accessible ingredients.
Paul Prudhomme — Louisiana Kitchen (for the seasoning); Italian-American adaptation