Start by placing your peeled and deveined shrimp into a large bowl. Drizzle with olive oil and generously sprinkle Cajun seasoning over the shrimp. Toss everything together until each piece is coated. Allow the shrimp to marinate for at least 15 minutes.

In a large pot, bring salted water to a rolling boil. Add the fettuccini pasta and cook according to package instructions for about 8-10 minutes, or until al dente. Once cooked, drain the pasta and set it aside, reserving a cup of pasta water for later use if needed.

In a large frying pan, melt 2 tablespoons of butter over medium heat. Add the sliced mushrooms and shallots, sautéing them for 5-7 minutes until they are tender and fragrant. Remove the sautéed vegetables from the pan and set aside.

In the same pan, add the marinated shrimp, spreading them out in a single layer. Cook for about 2-3 minutes, or until the shrimp turn pink and opaque. Remove the shrimp from the pan and set them aside.

Add ⅔ cup of chicken broth to the pan, scraping up any flavorful bits stuck to the bottom. Bring it to a boil and allow the broth to simmer for about 2-3 minutes until it thickens slightly.

In a small bowl, mix together the sour cream and cornstarch until smooth. Stir in 1 cup of chicken broth, then gradually add this mixture to the reduced broth in the pan. Continue stirring and simmer until the sauce thickens, about 3-5 minutes.

Return the cooked shrimp, sautéed mushrooms, roasted red bell peppers, and capers to the pan. Stir everything together and heat through for another minute or two.

Serve your Blackened Shrimp Stroganoff over the cooked fettuccini, spooning the creamy sauce and shrimp mixture generously over the pasta.