Cook fusilli in boiling salted water according to package directions. Drain and set aside.
On a medium-high setting, heat a large nonstick skillet. Toss the salmon in flour to coat very lightly. Heat the butter and oil in the skillet. When the butter melts, add the salmon and stir to coat with butter. Add the mushrooms and shallots to the pan. Toss gently. Sprinkle with salt and pepper. Add the white wine, lemon juice, tarragon, capers and broth. Cook, stirring gently until well-blended. Stir in sour cream and Worcestershire. Taste and adjust seasoning, as needed.
Add fusilli and toss gently. Divide into two servings and serve immediately.