How to Make It
Season the shrimp with salt and pepper. In a large skillet, melt 3 tablespoons of the butter in the olive oil over moderately high heat. Add half of the shrimp and cook, turning once, until lightly browned but not cooked through, 1 to 2 minutes. Transfer to a plate. Repeat with the remaining shrimp.
In the skillet, melt the remaining 3 tablespoons of butter. Add the shallots and garlic and cook over moderate heat, stirring occasionally, until softened and just starting to brown, about 5 minutes. Add the wine and Cognac and simmer until slightly reduced, about 2 minutes. Stir in the tomatoes, tomato paste and cayenne and simmer for 5 minutes, stirring occasionally. Add the shrimp and cook, stirring, until just cooked through, 3 to 5 minutes. Stir in the crème fraîche; season with salt and pepper. Serve with bread.
If you would like to flambé the Cognac, add it after the shrimp finish cooking in Step 2. Ignite carefully with a long-handled match and cook until the flames subside. Stir in the crème fraîche and serve.