Cook pasta according to package directions. Meanwhile, in a large skillet, saute mushrooms and onions in butter for 4-5 minutes or until tender. Add wine and garlic. Bring to a boil; cook until liquid is reduced by half, about 5 minutes.
Combine flour and water until smooth; gradually add to mushroom mixture. Bring to a boil. Reduce heat; cook and stir for 2 minutes or until thickened. Stir in cream. Bring to a boil. Reduce heat; simmer, uncovered, for 4-5 minutes or until heated through.
Add the pasta, chicken, capers, salt and pepper to cream sauce. Cook for 3-4 minutes or until heated through. Sprinkle with Parmesan cheese.