Marinate the shrimp in olive oil and Cajun seasoning for at least 15 minutes.

Cook the fettuccini pasta in salted boiling water until al dente, then drain and toss with olive oil.

Sauté chopped mushrooms and shallots in butter until tender, then set aside.

Cook the marinated shrimp in the same skillet until pink and charred, then remove from skillet.

Simmer chicken broth in skillet until reduced to about ¼ cup.

Mix sour cream with cornstarch, then stir into the reduced broth until thickened.

Combine shrimp, mushrooms, shallots, roasted peppers, and capers with the sauce.

Serve over fettuccini, garnished with fresh herbs if desired.