In a medium bowl, combine the shrimp with olive oil and Cajun seasoning, ensuring they are well-coated. Allow the shrimp to marinate for about 15 minutes.

While the shrimp marinates, bring a large pot of salted water to a rolling boil. Add the fettuccini pasta and cook for 8-10 minutes, or until al dente, stirring occasionally.

In a large skillet, melt 2 tablespoons of butter over medium heat. Add the sliced mushrooms and shallots, sautéing them for about 5-7 minutes until tender.

In the same skillet, add the marinated shrimp, spreading them out for even cooking. Cook for 2-3 minutes until the shrimp turn pink and opaque.

Pour in 1 cup of chicken broth to the skillet. Bring it to a boil, then reduce the heat until the broth reduces to about ¼ cup. Mix the sour cream and cornstarch with reserved broth and add back to the pan, cooking until thick.

Return the sautéed mushrooms, shallots, and cooked shrimp to the skillet with the creamy sauce. Add roasted bell peppers and capers, if using, and toss together over low heat.

Plate the cooked fettuccini pasta and generously top it with the Blackened Shrimp Stroganoff. Serve immediately.