Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente. Drain and set aside.
Heat butter or margarine in a large skillet. Add the shrimp, salt and pepper to taste and paprika. Stir with a wooden spatula. When the shrimp become pink (it should take 2 to 3 minutes), remove them with a slotted spoon, leaving the cooking liquid in the skillet.
Add red and green bell peppers, shallots, garlic and salt and pepper to taste. Cook, stirring, about 3 to 4 minutes over medium high heat. Add cognac and shrimp. Cook over medium heat for 2 more minutes.
Add sour cream and yogurt and blend all together. Add cilantro and bring to a simmer for about 30 seconds. Do not boil or sauce will separate. Serve over cooked fettuccine.
